U.S. patent number 6,879,149 [Application Number 10/091,579] was granted by the patent office on 2005-04-12 for wheel support bearing assembly.
This patent grant is currently assigned to NTN Corporation. Invention is credited to Masatoshi Mizutani, Takayuki Norimatsu, Hiroaki Ohba, Hisashi Ohtsuki, Koichi Okada, Toru Takahashi, Akira Torii.
United States Patent |
6,879,149 |
Okada , et al. |
April 12, 2005 |
**Please see images for:
( Certificate of Correction ) ** |
Wheel support bearing assembly
Abstract
A wheel support bearing assembly for rotatably supporting a
wheel 13 relative to a vehicle body structure 12 includes outer and
inner members 1 and 2 with dual rows of rolling elements 3
interposed therebetween. An electric generator 4 for generating an
electric power as one of the inner and outer members 1 and 2
rotates relative to the other of the inner and outer members 1 and
2 is utilized. The electric generator 4 includes a coil/magnetic
element combination 17, including a ring member accommodating a
coil therein, and a multi-pole magnet 18. A signal outputted from
the electric generator 4 and indicative of the number of
revolutions of the wheel 13 is transmitted wireless by a
transmitter 5. This transmitter 5 may be an annular
transmitter.
Inventors: |
Okada; Koichi (Iwata,
JP), Ohtsuki; Hisashi (Iwata, JP), Torii;
Akira (Iwata, JP), Norimatsu; Takayuki (Iwata,
JP), Ohba; Hiroaki (Iwata, JP), Takahashi;
Toru (Iwata, JP), Mizutani; Masatoshi (Iwata,
JP) |
Assignee: |
NTN Corporation (Osaka,
JP)
|
Family
ID: |
27346225 |
Appl.
No.: |
10/091,579 |
Filed: |
March 7, 2002 |
Foreign Application Priority Data
|
|
|
|
|
Mar 13, 2001 [JP] |
|
|
2001-069930 |
Apr 10, 2001 [JP] |
|
|
2001-111108 |
Jul 31, 2001 [JP] |
|
|
2001-231772 |
|
Current U.S.
Class: |
324/174;
384/448 |
Current CPC
Class: |
B60T
8/171 (20130101); B60T 8/329 (20130101); F16C
41/004 (20130101); F16C 41/007 (20130101); F16C
41/008 (20130101); G01P 3/443 (20130101); F16C
33/7879 (20130101); F16C 33/7886 (20130101); F16C
33/7896 (20130101); F16C 2326/02 (20130101); F16C
19/184 (20130101) |
Current International
Class: |
B60T
8/171 (20060101); B60T 8/32 (20060101); B60T
8/17 (20060101); G01P 3/42 (20060101); G01P
3/44 (20060101); G01P 003/54 () |
Field of
Search: |
;324/174 ;384/448
;73/514.39 ;303/20,168 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
196 34 714 |
|
Mar 1998 |
|
DE |
|
197 10 337 |
|
Sep 1998 |
|
DE |
|
0 569 924 |
|
Nov 1993 |
|
EP |
|
0 594 550 |
|
Apr 1994 |
|
EP |
|
1 177 959 |
|
Feb 2002 |
|
EP |
|
01-156464 |
|
Oct 1989 |
|
JP |
|
2001-151090 |
|
Jun 2001 |
|
JP |
|
WO 98/11356 |
|
Mar 1998 |
|
WO |
|
WO 99/49322 |
|
Sep 1999 |
|
WO |
|
Other References
Patent Abstracts of Japan, Publication No. 01-156464, Jun. 20,
1989, Shiga Shoji..
|
Primary Examiner: Le; N.
Assistant Examiner: Aurora; Reena
Attorney, Agent or Firm: Staas & Halsey LLP
Claims
What is claimed is:
1. An anti-skid braking device for, by detecting a rotational speed
of a wheel rotatably supported by an automotive body structure
using a wheel support bearing assembly rotatably supporting a wheel
relative to an automotive body structure and comprising an outer
member having an inner peripheral surface formed with plural rows
of raceways, an inner member having raceways defined therein in
face-to-face relation with the raceways in the outer member, plural
rows of rolling elements accommodated between the raceways in the
outer and inner members, an electric generator generating an
electric power as one of the outer and inner members rotates
relative to the other of the outer and inner members, and a
wireless transmitter transmitting wireless a signal indicative of a
number of revolutions of the wheel that is outputted from the
electric generator, controlling a braking force in response to a
detection signal indicative of the rotational speed of the wheel,
said anti-skid braking device comprising: a pulsar ring mounted on
a rotary member of a wheel, which serves as the inner member,
making up a part of the electric generator; a sensor mounted on a
wheel support member in face-to-face relation with the pulsar ring
and forming another part of the electric generator; the wireless
transmitter including a transmitter installed on the wheel support
member, and a receiver installed on the automotive body structure,
the transmitter transmitting the signal from the sensor by way of a
feeble radio wave, the receiver including a demodulating circuit
that provides the transmitted signal and a radio field strength
signal indicative of the field strength of the transmitted radio
wave; and a controller installed on the automotive body structure
determining a control of a braking force in dependence on the
sensor output signal and the radio field strength signal.
2. The anti-skid braking device as claimed in claim 1, wherein the
controller controls not to perform an anti-skid braking operation
unless a predetermined condition is satisfied in dependence on the
sensor output signal and the radio field strength signal.
3. The anti-skid braking device as claimed in claim 1, wherein the
controller determines the control in reference to a voltage of a
duplex signal in which the sensor output signal and the radio field
strength signal are duplexed.
4. The anti-skid braking device as claimed in claim 1, wherein the
transmitter transmits the feeble radio wave by frequency modulating
the sensor output signal, and the receiver detects the sensor
output signal and the radio field strength signal by demodulating
the feeble radio wave.
5. The anti-skid braking device as claimed in claim 1, wherein the
controller includes a software program describing procedures to
determine the control of the braking force in dependence on the
sensor output signal and the radio field strength signal, and a
computer capable of executing the software program.
6. The anti-skid braking device as claimed in claim 1, wherein the
pulsar ring is mounted on a rotation side bearing member of the
bearing assembly supporting the wheel rotatably, and the sensor is
mounted on a stationary side bearing member of the bearing
assembly.
7. A method of controlling an anti-skid braking device for, by
detecting a rotational speed of a wheel rotatably supported by an
automotive body structure using a wheel support bearing assembly
rotatably supporting a wheel relative to an automotive body
structure and comprising an outer member having an inner peripheral
surface formed with plural rows of raceways, an inner member having
raceways defined therein in face-to-face relation with the raceways
in the outer member, plural rows of rolling elements accommodated
between the raceways in the outer and inner members, an electric
generator generating an electric power as one of the outer and
inner members rotates relative to the other of the outer and inner
members, and a wireless transmitter transmitting wireless a signal
indicative of a number of revolutions of the wheel that is
outputted from the electric generator, controlling a braking force
in response to a detection signal indicative of the rotational
speed of the wheel, said method comprising: detecting a rotational
speed of the wheel by way of a pulsar ring mounted on a rotary
member of a wheel, which serves as the inner member, making up a
part of the electric generator, and a sensor mounted on a wheel
support member in face-to-face relation with the pulsar ring and
forming another part of the electric generator; wireless
transmitting causing a transmitter, installed on the wheel support
member, to transmit a feeble radio wave as a sensor output signal
outputted from the sensor, causing a receiver, installed on the
automotive body structure, and including a demodulating circuit to
receive the feeble radio signal to thereby detect the sensor output
signal and a radio field strength signal; determining, by way of a
controller installed on the automotive body structure, a control of
a braking force in dependence on the sensor output signal and the
radio field strength signal.
8. An anti-skid braking device, comprising: a wheel support bearing
assembly having rotatable and non-rotatable race members, and
plural rows of rolling elements accommodated between respective
raceways in the race members; a pulsar ring mounted on the
rotatable race member; a sensor mounted on a wheel support member
in face-to-face relation with the pulsar ring; an electric
generator generating an electric power as the race members rotate
relative to each other, and comprising the pulsar ring and the
sensor; a wireless transmitter including a transmitter installed on
the wheel support member, and a receiver installed on an automotive
body structure, the transmitter transmitting a signal from the
sensor by way of a feeble radio wave, the receiver including a
demodulation circuit and receiving the feeble radio wave to detect
a sensor output signal and a radio field strength signal; and a
controller installed on the automotive body structure determining a
control of a braking force in dependence on the sensor output
signal and the radio field strength signal.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wheel support bearing assembly
for use in an automotive vehicle and, more particularly, to the
wheel support bearing assembly including an electric generator that
serves as a means for detecting the number of revolution for an
anti-skid braking mechanism.
2. Description of the Prior Art
An anti-skid brake device (ABS), also referred to as an anti-lock
brake device, is known as used for detecting the incipiency of a
tire lock occurring on a low frictional road surface or at the time
of a panic stricken braking so that braking can be relieved to
secure a tire grip to thereby stabilize the steerability. A sensor
for detecting the number of revolutions of a wheel for detecting
the incipiency of the tire being locked is provided in a wheel
support bearing assembly. This sensor generally includes a pulsar
ring provided at an end portion or the like of a raceway in a
bearing outside, and a sensor portion provided in face-to-face
relation with the pulsar ring.
Also, as a wheel support bearing assembly having the sensor built
therein, such a bearing assembly as shown in FIG. 35 has hitherto
been suggested in, for example, the Japanese Laid-open Utility
Model Publication No. 1-156464. This known wheel support bearing
assembly includes, as shown in FIG. 35, a sensor portion 57
incorporated in a bearing outer race 51 which serves as a
stationary member. This known bearing assembly also includes an
outer race 51 for securement to a vehicle body structure, an inner
race 52 mounted on a shaft portion of a hub wheel 54, a plurality
of rolling elements 53 interposed between the inner race 51 and the
outer race 52, and a sealing member 60. The rotation sensor 55 is
of a structure wherein the sensor portion 57 is inserted into a
hole 58 defined in the outer race 51 so as to confront and align
with the pulsar ring 56 that is rigidly mounted on an outer
peripheral surface of the inner race 52. The use of the sensor
built in the bearing assembly is effective to reduce the size of
the wheel support bearing assembly as compared with the arrangement
in which the pulsar ring and the sensor portion are disposed at the
end of the bearing outside.
In the prior art wheel support bearing assembly having built
therein the sensor for detecting the number of revolutions of the
wheel, a wired interfacing system is generally employed in which
detection signals generated by the sensor and supply of an electric
power to the sensor are interfaced with the vehicle body structure
by means of a wiring. This is not an exception to the known wheel
support bearing assembly shown in FIG. 35, in which signal
interfacing and supply of the electric power are carried out by
means of an electric cable 59. As such, the known wheel support
bearing assembly makes use of the electric cable for drawing a
sensor output, and this electric cable is exposed to the outside of
the vehicle body structure at a location between the wheel support
bearing assembly and the vehicle body structure. Because of this,
the electric cable is susceptible to breakage by the effect of
stones hitting and/or frozen snow within a tire housing. Also, in
the case of a steering wheel, not only is it necessary for the
electric cable to be twisted beforehand, but often times a
relatively large number of processing steps is required. The
electric cable referred to above also requires a sheathing thereof
and, therefore, reduction in weight of an automotive vehicle tends
to be hampered and, in view of the large number of steps of fixing
the electric cable, a high cost tends to be incurred.
Also, although the known wheel support bearing assembly of the type
in which the sensor is built therein as shown in FIG. 35 can be
assembled relatively compact, servicing of the rotation sensor 55
requires dismantling of the outer and inner races 51 and 52 of the
wheel support bearing assembly, resulting in a problem that the
servicing cannot be performed efficiently. For this reason, once
the rotation sensor 55 fails to operate, the wheel support bearing
assembly as a whole would be required to replace with a new one. In
addition, although the known wheel support bearing assembly shown
in FIG. 35 is of the type wherein the rotation sensor is built
therein, since the sensor portion 57 is partly exposed outside the
bearing assembly, no sufficient reduction in size thereof is still
achieved. Yet, the known wheel support bearing assembly shown in
FIG. 35 has a problem in that sealing of the hole 58 defined in the
outer race 51 for receiving the sensor portion 57 is difficult to
achieve, making it difficult to prevent any ingress of foreign
matter.
In order to alleviate the foregoing problems, it may be
contemplated to use a wireless interfacing system such as disclosed
in, for example, the Japanese Patent Application No. 11-339588.
According to this application, the rotation sensor used therein is
of a type capable of transmitting signal wireless to a receiver. In
this wireless interfacing system, the modulation and the
directionality of the transmitted waves are carefully selected so
that the signal transmitted wireless from the rotation sensor will
not be affected adversely by external jamming radio waves.
However, even with the wireless interfacing system, any
countermeasures against the external jamming radio waves are
insufficient, and so is with illegal high power radio waves that
are difficult to suppress. As a result, there is no way of
determining whether or not the wireless transmitted signal
indicative of the number of revolution of the wheel has been
affected by the external jamming radio waves and, hence, there is a
high risk that the braking force cannot be properly controlled.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an improved wheel
support bearing assembly having a capability of detecting the
number of revolutions of a wheel, substantially free from cable
breakage occurring outside a vehicle body, and capable of being
assembled compact, excellent in servicing of the detecting means
for detection of the number of revolution of the wheel, and capable
of contributing to reduction in weight and cost of the automotive
vehicle.
Another object of the present invention is to provide an improved
anti-skid brake device and a method of controlling the same,
wherein a detection signal indicative of the number of revolutions
of the wheel can be transmitted wireless in the form of a feeble
electric signal and wherein the wheel support bearing assembly is
employed of a type capable of accurately controlling the braking
force without being accompanied by an erroneous operation which
would otherwise occur when a normal number of revolutions cannot be
recognized in reference to the received signal.
According to one aspect of the present invention, there is provided
a wheel support bearing assembly for rotatably supporting a wheel
relative to an automotive body structure. This wheel support
bearing assembly includes an outer member having an inner
peripheral surface formed with dual rows of raceways; an inner
member having raceways defined therein in face-to-face relation
with the raceways in the outer member; and dual rows of rolling
elements accommodated between the raceways in the outer and inner
members. An electric generator for generating an electric power as
one of the outer and inner members rotates relative to the other of
the outer and inner members is uniquely provided in combination
with a wireless transmitting means for transmitting wireless a
signal indicative of the number of revolutions of the wheel that is
outputted from the electric generator.
According to the structure, since the electric generator capable of
generating an electric power in response to a relative rotation
between the outer member and the inner member is employed, it is
possible to detect the number of revolutions of the wheel by the
utilization of an output of the electric generator as a signal
indicative of the number of revolutions of the wheel. Also, since
the use has been made of the wireless transmitting means for
transmitting wireless the signal outputted from the electric
generator, no electric cable for drawing the detection signal
indicative of the number of revolutions of the wheel to a control
unit is necessary. Also, since the electric generator is used as a
sensor, no electric power supply cable for the supply of an
electric power to the sensor is necessary. The electric power
obtainable from the electric generator can be used also as an
electric power for the wireless transmitting means. For these
reasons, no electric cable is exposed to the outside of the vehicle
body structure and there is no possibility of the cable being
broken, thereby eliminating any complicated and time-consuming
wiring job while contributing to reduction in weight and cost of
the automotive vehicle.
The wireless transmitting means which can be employed in the
practice of the present invention may not be always limited to a
type utilizing radio waves, but may be of a type capable of
transmitting by means of a magnetic coupling, infrared rays of
light, ultrasonic waves or any other signal that can travel in the
air.
In a preferred embodiment of the present invention, one of the
outer and inner members may have a wheel mounting flange. Also, one
of the outer and inner members may have a flange for securement of
the wheel support bearing assembly to the vehicle body structure.
By way of example, one of the outer and inner members may be
provided with the wheel mounting flange whereas the other of the
outer and inner member may be provided with a body fitting flange
for securement to the vehicle body structure. The wheel support
bearing assembly including the wheel mounting flange and the body
fitting flange is the one designed to achieve a light-weight
feature and a compact structure by unifying the component parts,
but the structure in which the electric generator for detection of
the rotational speed and the wireless transmitting means according
to the present invention is more effective in this wheel support
bearing assembly.
In one preferred embodiment of the present invention, the electric
generator may include a ring member made of a magnetic material and
accommodating a coil therein, and a multi-pole magnet and wherein
the ring member is mounted on one of the outer and inner members
and the multi-pole magnet is mounted on the other of the outer and
inner members.
The use of the multi-pole magnet in the electric generator makes it
possible to generate an alternating voltage of a frequency
proportional to the number of revolutions at a high frequency so
that the alternating frequency can be utilized efficiently to
detect the number of revolutions accurately. The use of the ring
member made of the magnetic material for accommodating the coil is,
when combined with the multi-pole magnet to form the electric
generator, effective to achieve an efficient generation of an
electric power.
Where the electric generator includes the ring member, made of the
magnetic material and accommodating therein the coil, and the
multi-pole magnet, the ring member and the multi-pole magnets is
preferably arranged between the dual rows of the raceways formed in
the outer and inner members.
Disposition of the ring member and the multi-pole magnet between
the dual rows of the raceways formed respectively in the outer and
inner members is effective to achieve a maximized utilization of
the space delimited between those rows of the raceways for
accommodating the electric generator in the wheel support bearing
assembly. Accordingly, the wheel support bearing assembly even
provided with the electric generator can be assembled compact.
Also, since the electric generator is made up of the ring member
and the multi-pole magnet, the electric generator as a whole can be
snugly and neatly accommodated within the wheel support bearing
assembly. In addition, there is no need to form an insertion hole
for inserting the sensor to a required position inside the wheel
support bearing assembly and, hence, the wheel support bearing
assembly embodying the present invention is substantially free from
a problem associated with possible ingress of foreign matter from
the outside into the wheel support bearing assembly through such
insertion hole.
Again, where the electric generator includes the ring member, made
of the magnetic material and accommodating therein the coil, and
the multi-pole magnet, at least one of the ring member and the
multi-pole magnet may be integrated together with a sealing member
for sealing an open end between the outer and inner members.
If the component part of the electric generator is integrated
together with the sealing member disposed at the open end between
the outer and inner members, mounting or removal of the electric
generator relative to the wheel support bearing assembly can be
facilitated and, hence, the servicing and repair of the electric
generator can easily be performed. For this reason, there is no
need to replace the wheel support bearing assembly with a new
assembly in the event of occurrence of any trouble. Also, the
freedom of mounting of the electric generator, that is, the freedom
of positioning and designing of the electric generator relative to
the wheel support bearing assembly can be increased, thereby
facilitating compactization of the wheel support bearing assembly.
Although mounting or removal of the electric generator may be
facilitated even if the electric generator is disposed at one end
portion of the outer and inner members, the presence of the
component parts of the electric generator separate from the sealing
member will make the assembly so bulky enough to hamper
compactization and will also require an increased number of
component parts accompanied by reduction in assemblability.
However, when the component part of the electric generator is
integrated together with the sealing member, the electric generator
can be snugly and neatly disposed with a reduced number of
component parts, resulting in an excellent assemblability.
Where at least one of the ring member and the multi-pole magnet is
formed integrally with the sealing member as hereinabove described,
an additional sealing member may also be employed for preventing an
ingress of foreign matter into a gap between the ring member and
the multi-pole magnet. The use of the additional sealing member is
effective to avoid any possible ingress of foreign matter into the
gap between the ring member and the multi-pole magnet to thereby
minimize damages to the electric generator.
In an alternative preferred embodiment of the present invention,
the ring member referred to above may have a sectional shape
similar to a groove shape or a shape of a figure "C", including a
casing portion, in which the coil is accommodated and which has
opposite side edges, and a plurality of comb-shaped prongs
extending outwardly from each of the opposite side edges of the
casing portion, and wherein the prongs extending outwardly from the
respective side edges of the casing portion are interleaved with
each other. By way of example, where the ring member has a
sectional shape representing a groove shape, each of opposite side
faces of the groove may have the plurality of the comb-shaped
prongs bent to extend towards a side face, with those comb-shaped
prongs integral with the respective side faces being alternated in
a direction circumferentially of the ring member.
The use of the ring member having the comb-shaped prongs is
effective to facilitate multi-polarization and compactization and
makes it possible to achieve an efficient generation of the
electric power with maximized utilization of magnetic fluxes. Since
the ring member having the comb-shaped prongs is employed in
combination with the multi-pole magnet, it is possible to achieve a
further efficient generation of the electric power. For this
reason, even when the electric power necessary to power the
transmitting means is secured from the electric generator of the
structure referred to above, a sufficient electric power can be
obtained.
Where the ring member is of the structure wherein the comb-shaped
prongs integral with the opposite side edges thereof alternate one
after another in the direction circumferentially of the ring
member, those comb-shaped prongs may be interleaved with each other
with a gap defined between one of the prongs extending from one of
the respective side edges and the neighboring one of the prongs
extending from the other of the respective side edges. The presence
of the gap between the neighboring prongs is effective to minimize
leakage of the magnetic fluxes, rendering the magnetic fluxes to be
maximally utilized.
Also, where the ring member is of the structure wherein the
comb-shaped prongs integral with the opposite side edges thereof
alternate one after another in the direction circumferentially of
the ring member, each of the comb-shaped prongs in the ring member
may have a width progressively decreasing in a direction towards a
free end of the respective prong.
If each of the comb-shaped prongs has a uniform width over the
entire length thereof, the magnetic flux density will increase at a
root portion thereof where it has been bent, with magnetic
saturation tending to occur. However, if each of the comb-shaped
prongs has a width progressively decreasing in a direction towards
a free end thereof, it is possible to render the magnetic
saturation to hardly occur at the root portion thereof. As a result
thereof, a further multi-polarization and compactization are
possible.
Again, where the electric generator includes the ring member, made
of the magnetic material and accommodating therein the coil, and
the multi-pole magnet, the ring member made of the magnetic
material and accommodating the coil of the electric generator may
include an annular magnetic pole portion coaxial therewith, in
which magnetic poles of different polarities alternate one after
another in a direction circumferentially thereof. In this case, two
multi-pole magnets are employed and positioned on respective sides
of the magnetic pole portion of the ring member. Where the ring
member is provided with the previously described comb-shaped
prongs, the arrangement of those comb-shaped prongs defines the
magnetic pole portion. The direction in which the magnetic pole
portion and the multi-pole magnets are oriented may be either an
axial direction or a radial direction.
If the ring member made of the magnetic material and accommodating
the coil has the multi-pole magnets disposed on the respective
sides of the magnetic pole portion thereof in the manner described
above, the surface area of the ring member confronting the
multi-pole magnets can increase to increase the magnetic fluxes
interlinking the coil and, therefore, the power output of the
electric generator can advantageously be increased.
In a preferred embodiment of the present invention, the
transmitting means may include an annular transmitter. As compared
with a box-type transmitter, for a given transmitter output, the
annular transmitter can have reduced sectional dimensions. In
generally, a fastening means such as, for example, knuckle for
securement to the automotive body structure, a constant speed
universal joint and so on are crowded in the vicinity of the wheel
support bearing assembly and, therefore, a relatively large space
is difficult to secure. However, if the transmitter is made annular
in shape, the sectional dimensions thereof can be reduced and,
therefore, the annular transmitter can be disposed by the
utilization of the limited space available in the wheel support
bearing assembly. Also, if the transmitter is made annular in
shape, even if the member on which the transmitter is mounted is a
member on a rotating side, signal transmission from the
transmitting means to the receiving means can be carried out
without being accompanied by a large variation in the received
signal.
Where the electric generator includes the ring member, made of the
magnetic material and accommodating therein the coil, and the
multi-pole magnet, the transmitting means may include an annular
transmitter, which is integrated together with the ring member
forming a part of the electric generator.
If the annular transmitter is integrated together with the ring
member of the electric generator, a combination of the electric
generator and the transmitting means can be assembled further
compact with the number of component parts reduced. For this
reason, the assemblability of the wheel support bearing assembly
increases.
In the practice of the present invention, where the electric
generator includes the ring member, made of the magnetic material
and accommodating therein the coil, and the multi-pole magnet, the
ring member and the transmitter may be arranged so as to overlap
with each other in a direction radially of the ring member.
If the transmitter is made annular, disposition of the transmitter
in this manner is effective to prevent a combination of the
transmitter and the ring member from protruding axially from the
wheel support bearing assembly, rendering it to be compact and,
therefore, the space around the wheel support bearing assembly can
be utilized maximally. By way of example, while the wheel support
bearing assembly used for supporting the drive axle is often
combined with the constant speed universal joint, a space available
between the wheel support bearing assembly and the constant speed
universal joint is generally small and, also, the circumference of
such space is small because of the presence of a member or members
used to secure the wheel support bearing assembly to the automotive
body structure. Accordingly, if the transmitter is made annular in
shape and disposed externally around the ring member, the limited
space between the wheel support bearing assembly and the constant
speed universal joint can be effectively and maximally utilized to
accommodate therein the transmitter.
Again, where the electric generator includes the ring member, made
of the magnetic material and accommodating the coil therein, and
the multi-pole magnet, the transmitting means may include an
annular transmitter that is integrated together with the ring
member. In this case, the ring member is fitted to an end portion
of the inner member. A sealing member for sealing an open end
between the inner and outer members may be fitted to the outer
member so as to be held in contact with an outer periphery of the
ring member.
If the sealing member is contacted to the ring member accommodating
therein the coil of the electric generator, to achieve a seal, the
ring member itself can perform a function as a sealing member and,
therefore, the structure required for sealing can further be
compactized.
Furthermore, where the electric generator includes the ring member,
made of the magnetic material and accommodating the coil therein,
and the multi-pole magnet, the transmitting means may include an
annular transmitter that is integrated together with the ring
member. In this case, the multi-pole magnet may be formed
integrally with a sealing member for sealing an open end between
the outer and inner members, and two components made up of an
assembly including the transmitter and the ring member and an
assembly including the multi-pole magnet and the sealing member may
then be used to seal the open end.
With this structure, since the sealing, the electric generator and
the transmitting means can be constituted by those two assemblies,
the number of component parts used can be reduced and, hence, the
assemblability is excellent.
According to another aspect of the present invention, there is
provided an anti-skid braking device for, by detecting a rotational
speed of a wheel rotatably supported by an automotive body
structure by means of the above discussed wheel support bearing
assembly, controlling a braking force in response to a detection
signal indicative of the rotational speed of the wheel. This
anti-skid braking device includes a pulsar ring mounted on a rotary
member of a wheel, which serves as the inner member, and
constituting a part of the electric generator; a sensor mounted on
a wheel support member in face-to-face relation with the pulsar
ring and forming another part of the electric generator; a wireless
transmitting means including a transmitting means installed on the
wheel support member, and a receiving means installed on the
automotive body structure; and a controller installed on the
automotive body structure for determining a control of a braking
force in dependence on a sensor output signal from the sensor and a
radio field strength signal. The transmitting means is operable to
transmit a signal from the sensor by means of a feeble radio wave,
whereas the receiving means receives the feeble radio wave to
detect the sensor output signal and the radio field strength
signal.
With this anti-skid braking device, the receiving means receives
the feeble radio wave and detects the sensor output signal and the
radio field strength signal. The controller is operable to
determine a control of a braking force in dependence on a sensor
output signal and a radio field strength signal. In this way, since
the receiving means is so designed as to output the radio field
strength signal, the controller can refer to the radio field
strength signal to detect that the number of revolutions cannot be
correctly recognized with the sensor output signal and, therefore,
the control of the braking force can be performed correctly.
In the practice of the present invention, the controller may be
designed to controls not to perform an anti-skid braking operation
unless a predetermined condition is satisfied in dependence on the
sensor output signal and the radio field strength signal.
By so doing, in the event of receipt of the jamming radio waves,
the possibility of the anti-skid braking operation being performed
erroneously can be avoided. Since the anti-skid braking operation
is an operation to relieve the braking action, the anti-skid
braking operation should be avoided for safety purpose where the
number of revolutions cannot be recognized correctly.
Also, in a preferred embodiment of the present invention, the
controller may determine the control in reference to a voltage of a
duplex signal in which the sensor output signal and the radio field
strength signal are duplexed.
Duplexing of those signals is effective to minimize the number of
wiring lines necessitated to connect the receiving means to the
controller. While in an automotive vehicle reduction in weight of
various component parts used therein is generally required,
reduction in number of the wiring lines leads to reduction in
weight of the automotive vehicle and also to reduction in number of
line connecting steps which in turn results in reduction in
cost.
In another preferred embodiment of the present invention, the
transmitting means may transmit the feeble radio wave by frequency
modulating the sensor output signal, whereas the receiving means
detects the sensor output signal and the radio field strength
signal by demodulating the feeble radio wave.
The use of the frequency modulating (FM) system makes it possible
to facilitate detection of the sensor output signal and the radio
field strength signal.
In a further preferred embodiment of the present invention, the
controller may include a software program describing procedures to
determine the control of the braking force in dependence on the
sensor output signal and the radio field strength signal, and a
computer capable of executing the software program.
Also, the pulsar ring may be mounted on a rotation side bearing
member of the bearing assembly supporting the wheel rotatably, in
which case the sensor is mounted on a stationary side bearing
member of the bearing assembly. The rotation side bearing member
and the stationary side bearing members provide respective parts
of, or respective entities of a rotational member and a wheel
support member of the wheel.
According to a further aspect of the present invention, there is
also provided a method of controlling an anti-skid braking device
for, by detecting a rotational speed of a wheel rotatably supported
by an automotive body structure by means of the previously
discussed wheel support bearing assembly, controlling a braking
force in response to a detection signal indicative of the
rotational speed of the wheel. This method includes a step of
detecting a rotational speed of the wheel by means of a pulsar ring
mounted on a rotary member of a wheel, which serves as the inner
member, and constituting a part of the electric generator, and a
sensor mounted on a wheel support member in face-to-face relation
with the pulsar ring and forming another part of the electric
generator; a wireless transmitting step of causing the transmitting
means, installed on the wheel support member, to transmit a feeble
radio wave as a sensor output signal outputted from the sensor,
causing the receiving means, installed on the automotive body
structure, to receive the feeble radio signal to thereby detect the
sensor output signal and a radio field strength signal; and a step
of determining, by means of a controller installed on the
automotive body structure, a control of a braking force in
dependence on the sensor output signal and the radio field strength
signal.
With this control method, the control of the braking force can be
performed correctly without being accompanied by an erroneous
operation which would otherwise occur when the number of
revolutions cannot be correctly recognized from the sensor output
signal.
BRIEF DESCRIPTION OF THE DRAWINGS
In any event, the present invention will become more clearly
understood from the following description of preferred embodiments
thereof, when taken in conjunction with the accompanying drawings.
However, the embodiments and the drawings are given only for the
purpose of illustration and explanation, and are not to be taken as
limiting the scope of the present invention in any way whatsoever,
which scope is to be determined by the appended claims. In the
accompanying drawings, like reference numerals are used to denote
like parts throughout the several views, and:
FIG. 1 is a longitudinal sectional view of a wheel support bearing
assembly according to a first preferred embodiment of the present
invention;
FIG. 2 is an endwise view of the wheel support bearing assembly as
viewed from a direction of a constant speed universal joint
employed therein;
FIG. 3A is a longitudinal sectional view of a multi-pole magnet of
an electric generator;
FIG. 3B is a front elevational view of the multi-pole magnet shown
in FIG. 3A;
FIG. 4A is a fragmentary side view of a ring member forming a part
of the electric generator;
FIG. 4B is a front elevational view of the ring member shown in
FIG. 4A;
FIG. 5A is an enlarged view showing a portion of FIG. 4A;
FIG. 5B is an enlarged view showing a portion of FIG. 4B;
FIG. 6A is a fragmentary side view showing a modification of the
ring member used in the electric generator;
FIG. 6B is a front elevational view of the modified ring member
shown in FIG. 6A;
FIG. 6C is a fragmentary enlarged view showing a portion of the
modified ring member shown in FIG. 6B;
FIG. 7A is a longitudinal sectional view of the wheel support
bearing assembly according to a second preferred embodiment of the
present invention;
FIG. 7B is an enlarged sectional view showing a portion of the
wheel support bearing assembly shown in FIG. 7A;
FIG. 8 is a fragmentary front elevational view of one of radial
halves of an elastic member which forms the multi-pole magnet of
the electric generator used in the bearing assembly shown in FIG.
7A;
FIG. 9A is a fragmentary longitudinal sectional view of the wheel
support bearing assembly according to a third preferred embodiment
of the present invention, showing only one of longitudinal halves
thereof;
FIG. 9B is a fragmentary enlarged sectional view of a portion of
the wheel support bearing assembly shown in FIG. 9A;
FIG. 10 is a fragmentary sectional view of the wheel support
bearing assembly according to a fourth preferred embodiment of the
present invention, showing only one of longitudinal halves
thereof;
FIG. 11 is a fragmentary sectional view of the wheel support
bearing assembly according to a fifth preferred embodiment of the
present invention, showing only one of longitudinal halves
thereof;
FIG. 12 is a fragmentary sectional view of the wheel support
bearing assembly according to a sixth preferred embodiment of the
present invention, showing only one of longitudinal halves
thereof;
FIG. 13 is a fragmentary sectional view of the wheel support
bearing assembly according to a seventh preferred embodiment of the
present invention, showing only one of longitudinal halves
thereof;
FIG. 14 is a fragmentary sectional view of the wheel support
bearing assembly according to an eighth preferred embodiment of the
present invention, showing only one of longitudinal halves
thereof;
FIG. 15 is a fragmentary sectional view of the wheel support
bearing assembly according to a ninth preferred embodiment of the
present invention, showing only one of longitudinal halves
thereof;
FIG. 16A is a fragmentary longitudinal sectional view of the wheel
support bearing assembly according to a tenth preferred embodiment
of the present invention, showing only one of longitudinal halves
thereof;
FIG. 16B is a fragmentary enlarged sectional view of a portion of
the wheel support bearing assembly shown in FIG. 16A;
FIG. 17A is a fragmentary longitudinal sectional view of the wheel
support bearing assembly according to an eleventh preferred
embodiment of the present invention, showing only one of
longitudinal halves thereof;
FIG. 17B is a fragmentary enlarged sectional view of a portion of
the wheel support bearing assembly shown in FIG. 17A;
FIG. 18 is a fragmentary sectional view of the wheel support
bearing assembly according to a twelfth preferred embodiment of the
present invention, showing only one of longitudinal halves
thereof;
FIG. 19A is a fragmentary longitudinal sectional view of the wheel
support bearing assembly according to a thirteenth preferred
embodiment of the present invention, showing only one of
longitudinal halves thereof;
FIG. 19B is a fragmentary enlarged sectional view of a portion of
the wheel support bearing assembly shown in FIG. 19A;
FIG. 20 is a fragmentary longitudinal sectional view of the wheel
support bearing assembly according to a fourteenth preferred
embodiment of the present invention, showing only one of
longitudinal halves thereof;
FIG. 21 is a fragmentary longitudinal sectional view of the wheel
support bearing assembly according to a fifteenth preferred
embodiment of the present invention, showing only one of
longitudinal halves thereof;
FIG. 22 is a fragmentary longitudinal sectional view of the wheel
support bearing assembly according to a sixteenth preferred
embodiment of the present invention, showing only one of
longitudinal halves thereof;
FIG. 23 is a fragmentary longitudinal sectional view of the wheel
support bearing assembly according to a seventeenth preferred
embodiment of the present invention, showing only one of
longitudinal halves thereof;
FIG. 24 is a fragmentary longitudinal sectional view of the wheel
support bearing assembly according to an eighteenth preferred
embodiment of the present invention, showing only one of
longitudinal halves thereof;
FIG. 25A is a fragmentary longitudinal sectional view of the wheel
support bearing assembly according to a nineteenth preferred
embodiment of the present invention, showing only one of
longitudinal halves thereof;
FIG. 25B is a fragmentary enlarged sectional view of a portion of
the wheel support bearing assembly shown in FIG. 25A;
FIG. 26 is a fragmentary perspective view of a ring member employed
in the wheel support bearing assembly shown in FIG. 25A;
FIG. 27 is a fragmentary perspective view of the ring member shown
in FIG. 26, as viewed in a direction opposite to that viewed in
FIG. 26;
FIG. 28 is a schematic diagram showing a conceptual construction of
an anti-skid brake device employing the wheel support bearing
assembly of the present invention shown in combination with a
control system therefore;
FIG. 29 is a block circuit diagram showing a wireless transmission
system employed in the practice of the present invention;
FIG. 30 is a chart showing various waveforms appearing during the
operation of the wireless transmission system shown in FIG. 29;
FIG. 31 is a circuit diagram showing an example of an output
circuit employed in the wireless transmission system shown in FIG.
29;
FIG. 32 is a chart showing a waveform appearing in the circuit
shown in FIG. 31;
FIG. 33 is a circuit diagram showing another example of the output
circuit that can be employed in the wireless transmission system
shown in FIG. 29:
FIG. 34 is a chart showing a waveform appearing in the circuit
shown in FIG. 33; and
FIG. 35 is a longitudinal sectional view of the prior art wheel
support bearing assembly.
DETAILED DESCRIPTION OF THE EMBODIMENTS
A first preferred embodiment of the present invention will now be
described with reference to FIGS. 1 to 5. This embodiment is
directed to an inner race rotating type of the fourth generation
and is illustrative of application to a bearing assembly for
support of a drive wheel. This embodiment corresponds to the
invention as defined in claim 5.
As shown in FIG. 1, the wheel bearing assembly shown therein is of
a design in which a plurality of, for example, two, rows of rolling
elements 3 are rollingly interposed between an outer member 1 and
inner member 2, an electric generator 4 which concurrently serves
as a rotation sensor is disposed within an annular space defined
between the outer and inner members 1 and 2, and a wireless
transmitting means 5 is provided for transmitting wireless a
rotational signal indicative of the number of revolutions outputted
from the electric generator 4. The electric generator 4 is disposed
generally intermediate between the rows of the rolling elements 3
and 3.
The outer member 1 has an inner peripheral surface formed with a
plurality of, for example, two, rows of raceways 6 and 7, and
raceways 8 and 9 opposed respectively to the raceways 6 and 7 are
defined in an outer peripheral surface of the inner member 2. The
rows of the rolling elements 3 are rollingly accommodated between
the raceways 6 and 8 and between the raceways 7 and 9,
respectively. The wheel bearing assembly shown therein is of a type
generally referred to as a double row angular contact ball bearing
assembly, wherein the raceways 6 to 9 have their respective contact
angles so defined as to achieve a back-to-back alignment. The
rolling elements 3 are rollingly retained by retainers or cages 10
employed one for each row of the rolling elements 3. Opposite ends
of the inner and outer members 2 and 1 are tightly sealed by
respective sealing members 11 and 11A.
The outer member 1 has one end formed with a radially outwardly
extending vehicle body fitting flange 1a formed therewith for
connection with an automotive body structure. Specifically, the
vehicle body fitting flange 1a integral with the outer member 1 is
adapted to be secured to a wheel bearing support member 12a such
as, for example, a knuckle of the automotive body structure 12. It
is to be noted that the outer member 1 is of one-piece structure
including the vehicle body fitting flange 1a. On the other hand,
the inner member 2 has a wheel mounting flange 2a protruding
radially outwardly therefrom, to which mounting flange 2a is bolted
a wheel 13 by means of a plurality of bolts 14.
The inner member 2 includes a hub wheel 2A formed integrally with
the wheel mounting flange 2a and another inner race forming member
2B combined with the hub wheel 2A to define the inner member 2. The
raceways 8 and 9 are formed on the hub wheel 2A and the inner race
forming member 2B, respectively. The inner race forming member 2B
is a member formed integrally with an outer race 15a of a constant
speed universal joint 15, and an inner race (not shown) of the
constant speed universal joint 15 is coupled with a drive shaft
(not shown). FIG. 2 illustrates the wheel support bearing assembly
as viewed from a direction of the constant speed universal joint 15
employed therein. The inner race forming member 2B has a hollow
shaft portion 16 extending integrally from the outer race 15a of
the constant speed universal joint 15. The hollow shaft portion 16
has a large diameter portion 16a adjacent the constant speed
universal joint 15 and a reduced diameter portion 16b continued
from the large diameter portion 16a through a radial step with the
hub wheel 2A mounted on the reduced diameter portion 16b. The
raceway 9 referred to hereinabove is formed on the large diameter
portion 16a. The hub wheel 2A and the inner race forming member 2B
are integrated together by means of a plastic coupling such as, for
example, by the use of an interference fit (a staking
technique).
The electric generator 4 is of a structure wherein a multi-pole
magnet 18 is disposed radially inwardly of and in face-to-face
relation with a ring-shaped coil/magnetic element combination 17
having a coil built therein. The coil/magnetic element combination
17 is fitted to an inner peripheral surface of the outer member 1,
which is a member on a stationary side, and serves as a stator of
the electric generator 4. The multi-pole magnet 18 is fitted to an
outer peripheral surface of the inner member 2, which is a member
on a rotatable side, and, more specifically, to an outer peripheral
surface of the hub wheel 2A and serves as a rotor of the electric
generator 4.
The wireless transmitting means 5 is provided on a circumferential
portion of the outer peripheral surface of the outer member 1 and
includes a transmitter having electronic component parts enclosed
within an outer casing. The outer casing referred to above is of a
box-like configuration and is provided with a transceiver antenna
(not shown) enclosed therein. This wireless transmitting means 5
is, for example, a transmitter capable of transmitting signals of
feeble radio waves. The signal may be of a kind capable of turning
on and off radio waves or of a kind capable of modulating a carrier
wave on a frequency modulation scheme or the like. Other than that
capable of transmitting radio waves, the wireless transmitting
means 5 may be of a kind capable of transmitting by means of a
magnetic coupling, transmitting light, for example, infrared rays
of light, transmitting ultrasonic waves, or any other transmitter
capable of transmitting signals in the air. As an electric power
source for the wireless transmitting means 5, the electric
generator 4 is used. A receiving means (not shown) cooperable with
the wireless transmitting means 5 is installed in, for example, a
tire housing (not shown) in the automotive body structure, and
signals from the receiving means can be transmitted to a control
unit of an anti-skid brake system. The receiving means is fixed at
a position within an unobstructed field of view of the transmitting
means 5 with no metallic obstruction intervening therebetween, so
that the signals such as radio waves transmitted from the
transmitting means 5 can be efficiently received by the receiving
means. Cables (not shown) for supplying an electric power generated
from the electric generator 4 and also for outputting a rotation
detection signal are connected between the transmitting means 5 and
the coil of the coil/magnetic element combination 17 of the
electric generator 4. These cables are passed through a cable hole
(not shown) formed in a peripheral wall of the outer member 1 so as
to extend completely thereacross in a direction radially thereof,
with the cable hole being sealed by a sealant such as an elastic
material or a wet-type sealant. It is, however, to be noted that
connectors may be employed in place of the cables.
For the electric generator 4, that shown in, for example, any one
of FIGS. 3 to 5 can be used. As shown in FIG. 3, the multi-pole
magnet 18 is a ring-shaped member having N and S poles arranged
alternately in a direction circumferentially thereof.
The coil/magnetic element combination 17 shown in FIG. 4 is
referred to as a claw pole type in which a plurality of magnetic
poles made up of claws 21a and 21b of a pole shape are arranged
alternately. FIGS. 5A and 5B are diagrams which show respective
portions of FIGS. 4A and 4B on an enlarged scale.
More specifically, the coil/magnetic element combination 17
includes a ring member 19 made of a magnetic material and a coil 20
accommodated within the ring member 19. The ring member 19 has a
sectional shape resembling to a groove shape oriented towards an
inner periphery thereof, that is, the ring member 19 is of a
generally U-shaped section opening radially inwardly while having
radially inwardly extending annular flanges 19a and 19b forming
respective side walls of the ring member 19. Inner peripheral edges
of the annular flanges 19a and 19b are formed with respective
comb-shaped claws 21a and 21b so as to extend in respective
directions opposed to each other such that the comb-shaped claws
21a integral with the annular flange 19a are interleaved with the
comb-shaped claws 21b integral with the annular flange 19b in a
direction circumferentially of the ring member 19, with all of
those claws 21a and 21b being spaced an equal distance from each
other in the circumferential direction of the ring member 19. Each
line of the comb-shaped claws 21a and 21b forms an annular magnetic
pole respectively. Each of the comb-shaped claws 21a and 21b is of
a rectangular shape having its longitudinal axis extending parallel
to the direction of extension of such claws 21a and 21b. The
neighboring claws 21a or 21b are spaced a gap d of a width that is
chosen to be, for example, three times the width of each of the
claws 21a and 21b.
The inner peripheral edge of each of the annular flanges 19a and
19b of the ring member 19 is formed with a cutout 22a or 22b that
is defined between the neighboring claws 21a or 21b so that a free
end of each opposite claw 21b or 21a can be positioned within the
corresponding cutout 22a or 22b. Each of those cutouts 22a and 22b
is preferably of a semicircular shape or a generally U-shape.
This ring member 19 of the structure described above can be
prepared from a metal plate of a magnetic material such as, for
example, stainless plate by the use of a press work.
It is to be noted that although the ring member 19 is shown as
divided into two components along a mid-center line passing
intermediate of the width thereof, that is, at the center of a web,
it may be of one-piece structure.
With the wheel bearing assembly of the structure described above,
since the electric generator 4 is employed, which generate
electricity when one of the outer and inner members 1 and 2 rotates
relative to the other of the outer and inner members 1 and 2, the
number of revolutions of the wheel can be detected by utilizing an
output from the electric generator 4 as a signal indicative of the
number of revolutions of the wheel 13. Since the electric generator
4 is built in the annular space between the outer member 1 and the
inner member 2, the bearing assembly can be assembled compact while
securing a function of detecting the number of revolutions. Also,
since the transmitting means 5 for transmitting wireless the
detection signal indicative of the number of revolutions of the
wheel that is outputted from the electric generator 4, no electric
cable which would be necessitated to supply the detection signal
indicative of the number of revolutions to the control unit is
needed.
Also, an electric power generated by the electric generator 4 is
used as an electric power source for the wireless transmitting
means 5 and, therefore, no electric cable for supplying the
electric power from the automotive body structure 12 to the
wireless transmitting means 5A is needed. For these reasons, no
electric line is exposed outside the automotive body structure,
there is no possibility of the electric line being broken, no
complicated and time-consuming wiring job is required, the
automobile can be manufactured lightweight and the cost thereof can
be reduced. Also, since the electric generator 4 in its entirety is
built in the annular space delimited between the outer and inner
members 1 and 2, no hole which would otherwise be necessitated for
exposure of a portion of the electric generator 4 to the outside is
necessary, resulting in increase of the sealability.
The hole through which the cable between the electric generator 4
and the wireless transmitting means 5A is passed would be required
to be formed in the outer member 1, but since the hole for passage
of an electric wire therethrough suffices to be a small hole, the
sealing can be achieved easily.
The electric generator 4 is of the structure wherein the
coil/magnetic element combination 17 includes the ring member 19
having the interleaved claws 21a and 21b, and the coil 20, which is
used in combination with the ring-shaped multi-pole magnet 18.
Accordingly, it is easy to attain multi-polarization and
compactization and the efficient power generation excellent in
efficiency of utilization of magnetic fluxes can be achieved. In
particular, since the coil/magnetic element combination 17 is of
the structure wherein the gaps between the interleaved claws 21a
and 21b are chosen to be so large as to minimize leakage of
magnetic fluxes from the neighboring magnetic poles, the efficiency
of utilization of the magnetic fluxes can be high.
In place of the structure discussed hereinabove, the electric
generator 4 may be of a structure wherein the coil/magnetic element
combination 17 is assembled as shown in FIG. 6. The coil/magnetic
element combination 17 shown in FIG. 6 is featured in that each of
the interleaved claws 21 and 21b of the ring member 19 is so shaped
as to have its width progressively decreasing in a direction
towards its free end, that is, outwardly tapered.
The ring member 19 is divided into and made up of a pair of ring
segments 19A and 19B. Each of the ring segments 19A and 19B has the
corresponding annular flange 19a or 19b and a plurality of web
forming pieces 19ca or 19cb extending radially from an outer
peripheral edge thereof, and the ring segments 19A and 19B are
combined together with the web forming pieces 19ca and 19cb
overlapped with each other partly in a widthwise direction thereof.
Each of the ring segments 19A and 19B has its inner peripheral edge
of the corresponding annular flange 19a or 19b formed with
comb-shaped claws 21a or 21b that are bent to protrude in a
direction perpendicular to the respective annular flange 19a or
19b. With the ring segments 19A and 19B combined together in the
manner described, the comb-shaped claws 21a and 21b integral with
the respective flanges 19a and 19b are interleaved with each other
at intervals of a predetermined gap in a direction
circumferentially thereof.
Other structural features of the coil/magnetic element combination
17 shown therein are substantially similar to those in the
coil/magnetic element combination 17 shown in and described with
reference to FIGS. 4 and 5. Corresponding parts of the
coil/magnetic element combination 17 shown in FIG. 6 are designated
by like reference numerals used in connection with the
coil/magnetic element combination 17 shown in FIGS. 4 and 5.
Comparing the coil/magnetic element combination 17 having the
rectangular claws 21a and 21b as shown in FIGS. 4 and 5 with the
coil/magnetic element combination 17 having the tapering claws 21a
and 21b as shown in FIG. 6, there is the following merits and
demerits.
In the case of the coil/magnetic element combination 17 having the
rectangular claws 21a and 21b as shown in FIGS. 4 and 5, it is
considered best in terms of the efficiency of utilization of the
magnetic fluxes, but the magnetic flux density at root portions of
the claws 21a and 21b where the latter are bent from the associated
annular flanges 19a and 19b tends to be high and, accordingly, they
must have to a certain extend a sectional area enough to avoid
magnetic saturation. For this reason, multipolarization and
reduction in size are limited.
In the case of the coil/magnetic element combination 17 having the
tapering claws 21a and 21b as shown in FIG. 6, no magnetic
saturation occur at the root portions of the claws 21a and 21b and,
therefore, multipolarization and reduction in size are possible. In
other words, since the strength of the magnetic field between the
neighboring N and S pole magnets represents a sinusoidal shape, the
magnetic field at a transit point between the N pole and the S pole
is very weak and, therefore, based on the assumption that no
influence will be brought about even when leakage into the
neighboring magnetic pole claws 21a and 21b, the claws 21a and 21b
are tapered so that no magnetic saturation will occur at the root
portions.
The reason that the ring member 19 is rendered to be a split type
is only for the purpose of processing, but in the example shown in
FIG. 6, the ring member 19 may be an integral part. Also, in the
example as shown in FIG. 6, the ring segments 19A and 19B may be
butted together by means of web portions 19c as is the case with
that shown in FIGS. 4 and 5. Also, in the example shown in FIGS. 4
and 5, the ring member 19 may be of a split type with the web
forming pieces partially overlapped with each other as is the case
with that shown in FIG. 6.
In the foregoing embodiment, the electric generator 4 has been
arranged between the plural raceways. However, the electric
generator 4 may be provided at an open end between the inner and
outer members 2 and 1 as shown in the following various embodiments
as will be described later.
Also, in the foregoing embodiment, the wireless transmitting means
5 has been used in the form of a box-type transmitter provided in a
portion of the circumferential direction, but the wireless
transmitting means 5 may be in the form of an annular transmitter.
In such case, the annular transmitter may be integrated together
with the ring member 19 of the electric generator 4.
In the next place, various embodiments of the present invention
will be described in which the electric generator 4 is used as a
component part of the seal 11 and the wireless transmitting means 5
is employed in the form of an annular transmitter and is integrated
together with the ring member of the electric generator 4.
FIGS. 7 to 22 illustrates such other embodiments of the present
invention, respectively. In the first place, what is common to
those embodiments will be described. In each of those embodiments,
the wheel support bearing assembly includes the outer member 1
having the double raceways 6 and 7 defined on the inner peripheral
surface thereof, the inner member 2 having the raceways 8 and 9
opposed respectively to the raceways 6 and 7, and the rows of the
rolling elements 3 rollingly accommodated between the raceways 6
and 8 and between the raceways 7 and 9, and is used to rotatably
support the wheel relative to the automotive body structure 12.
This wheel support bearing assembly is in the form of a double row
angular ball bearing with the contact angles of the raceways 6 to 9
so defined as to achieve the back-to-back alignment. Each of the
rows of the rolling elements 3 is rollingly retained in position by
the corresponding retainer or cage 10. The annular space defined
between the inner and outer members 2 and 1 has opposite open ends
sealed by respective sealing members 11 and 11A. The sealing member
11 is used to seal the open end on an inboard side whereas the
sealing member 11A is used to seal the open end on an outboard
side.
The electric generator 4 is employed which generates an electric
power upon rotation of one of the outer and inner members 1 and 2
relative to the other of the outer and inner members 1 and 2, and
the wireless transmitting means 5 is also employed for transmitting
wireless the signal indicative of the number of revolutions of the
wheel outputted from the electric generator 4.
The electric generator 4 is made up of the ring member 19 made of a
magnetic material and accommodating the coil 20 and a ring-shaped
multi-pole magnet 18. The ring member 19 is mounted on one of the
outer member 1 and the inner member 2 whereas the multi-pole magnet
18 is mounted on the other of the outer member 1 and the inner
member 2. The electric generator 4 may be either a thrust type in
which the direction in which the coil/magnetic element combination
17 and the multi-pole magnet 18 are opposed to each other, that is,
the direction in which magnetic poles are oriented lie in an axial
direction of the bearing assembly, or of a radial type in which it
lies in a radial direction of the bearing assembly.
At least one of the ring member 19 and the multi-pole magnet 18 is
formed integrally with a sealing member which forms a part of the
sealing member 11 used to close the open end between the outer and
inner members 1 and 2.
The transmitting means 5 is constituted by an annular transmitter
5A, and this transmitter 5A is integrated together with the ring
member 19 forming the electric generator 4. The transmitter 5A and
the coil 20 are connected together by means of an electric wire or
a connection connector (not shown).
Hereinafter, the various embodiments of the present invention will
be described.
FIG. 7 illustrates a second preferred embodiment of the present
invention. The wheel support bearing assembly according to this
embodiment is an inner race rotating type of a third generation and
is used for the support of the drive axle. The electric generator 4
is the thrust type. This second embodiment corresponds to the
invention of Claim 13.
The outer member 1 has a vehicle body fitting flange 1a which is,
as is the case with the first embodiment, adapted to be fitted to a
wheel bearing support component 12a such as, for example, knuckle
of the automotive body structure 12. The inner member 2 includes a
hub wheel 2A, and a separate inner race forming member 2C mounted
on an outer periphery of the end of the hub wheel 2A. The hub wheel
2A has a wheel mounting flange 2a formed integrally therewith. The
raceways 8 and 9 on the inner member 2 are formed on the hub wheel
2A and the inner race forming member 2C, respectively.
The inner member 2 is coupled with an outer ring 15a of the
constant speed universal joint 15 that is manufactured separate
from the wheel support bearing assembly. The outer ring 15a of the
constant speed universal joint 15 has a shaft portion 16 formed
integrally therewith so as to extend from outer bottom portion
thereof, which shaft portion 16 is inserted into an inner
peripheral surface of the hub wheel 2A and is then fixed in
position by means of a nut fastened thereto to thereby connect it
with the inner member 2. A flat step 16c formed in the outer bottom
portion of the outer ring 15a of the constant speed universal joint
15 so as to orient axially thereof is held in abutment with an end
face of the inner race forming member 2C to lock the inner race
forming member 2c in position.
The sealing member 11 on the bearing backside includes, as shown in
FIG. 7B on an enlarged scale, first and second annular sealing
members 31 and 32 fitted to the inner and outer members 2 and 3,
respectively. These seal members 31 and 32 are fitted in position
as press-fitted into the inner and outer members 2 and 3,
respectively. Each of the sealing members 31 and 32 is in the form
of a plate-like member and is formed so as to represent a generally
L-sectioned shape having a cylindrical portion 31a or 32a and an
upright plate portion 31b or 32b, with the sealing members 31 and
32 opposing to each other.
The first sealing member 31 is mounted on the inner member 2 which
is a member on a rotating side of the inner and outer members 2 and
1. The upright plate portion 31b of the first sealing member 31 is
arranged outwardly of the bearing assembly and has an outer side
face thereof provided with a magnet member 34 of the multi-pole
magnet 18. This magnet member 34 forms the multi-pole magnet 18 of
the electric generator 4 together with the first sealing member 31,
and the first sealing member 31 is made of a magnetic material. The
magnet member 34 is formed with magnetic poles N and S alternating
in a circumferential direction thereof as shown in FIG. 8, and the
magnetic poles N and S are arranged in a circle having a pitch
circle diameter (PCD) and spaced at intervals of a predetermined
pitch p. By disposing the coil/magnetic element combination 17 in
face-to-face relation with the magnet member 34 of the multi-pole
magnet 18 as shown in FIG. 7B, the electric generator 4
concurrently serving as a rotation sensor can be formed.
The magnet member 34 of the multi-pole magnet 18 is made of an
elastic member mixed with a powder of magnetic material and is
vulcanized to be bonded the first sealing member 31 to form a
so-called rubber magnet. It is, however, to be noted that instead
of vulcanization the magnet member 34 of the multi-pole magnet 18
may be prepared by hardening a mass of magnetic powders with the
use of a bonding material (neodymium bond magnet), which may be
subsequently bonded and fixed in position to the first sealing
member 31.
The second sealing member 32 has formed integrally therewith a side
lip 36a, slidingly engaged with the upright plate portion 31b of
the first sealing member 31, and radial lips 36b and 36c slidingly
engaged with the cylindrical portion 31a of the first sealing
member 31. These lips 36a to 36c are provided as respective
portions of the elastic member 36 vulcanized to be bonded the
second sealing member 32. The cylindrical portion 32a of the second
sealing member 32 and a free end of the upright plate portion 31b
of the first sealing member 31 are spaced radially a slight
distance to define a labyrinth seal 37.
The coil/magnetic element combination 17 includes the ring member
19 made of a magnetic material and accommodating the coil 20. The
ring member 19 is identical with the ring member 19 used in the
coil/magnetic element combination 17 described in connection with
the first embodiment (FIG. 1) with reference to FIGS. 4 and 5,
except that the different direction of orientation of the magnetic
polarities is used. In other words, the ring member 19 shown in
FIG. 7 has a cross sectional shape similar to a groove as is the
case with the ring member 19 in the example of FIGS. 4 and 5 and
has a plurality of comb-shaped claws 21a and 22a that are bent from
respective open edges of side face of the groove in a direction
conforming to the opposite side faces so that the claws 21a and 22a
can be alternately interleaved with each other in a direction
circumferential of the ring member 19. It is, however, to be noted
that the coil/magnetic element combination 17 used in the
embodiment of FIG. 7 has, unlike that in FIGS. 4 and 5, the groove
opening oriented axially thereof and the magnetic poles defined by
the interleaved claws 21a and 22a are oriented axially accordingly.
Even in the ring member 19 used in the embodiment of FIG. 7, the
interleaved claws 21a and 22a may be tapered as is the case with
those shown in FIG. 6.
Referring now to FIG. 7B, the coil/magnetic element combination 17
is fitted to a fitting ring 49 through the ring member 19, and the
annular transmitter 5A in the transmitting means 5 is fitted to
this fitting ring 49. Thus, when the transmitter 5A and the ring
member 19 of the coil/magnetic element combination 17 are fitted to
the same fitting ring 49, the transmitter 5A and the ring member 19
of the coil/magnetic element combination 17 can be integrated
together. The annular transmitter 5A is arranged on an outer
periphery of the ring member 19.
The fitting ring 49 is a molded component of metal and has a
transversely oriented groove-shaped portion 49a, in which the
coil/magnetic element combination 17 is engaged, and a reverse
L-shaped portion 49b extending radially outwardly from an outer
peripheral open edge of the groove-shaped portion 49a and extending
in the same direction as in which the groove-shaped portion 49a
opens. This fitting ring 49 is fitted to the outer member 1 with
the reverse L-shaped portion 49b press-fitted into an outer
peripheral surface of an end portion of the outer member 1. By this
press-fitting, the coil/magnetic element combination 17 can be
positioned in face-to-face relation with the open end between the
outer member 1 and the inner member 2 and, hence, in face-to-face
relation with the multi-pole magnet 18 while the transmitter 5A is
positioned in face-to-face relation with an end face of the outer
member 1.
This fitting ring 49 substantially enclose the end opening between
the outer member 1 and the inner member 2 and concurrently serves
as a sealing means for this end opening, and a sealing member 38
for covering the remaining gap between the fitting ring 49 and the
inner member 2 is fitted to an inner peripheral open edge of the
groove-shaped portion 49a of the fitting ring 49. The sealing
member 38 is made of an elastic material such as, for example,
rubber and is held in sliding engagement with the end face of the
inner member 2. This sealing member 38 is used to prevent foreign
matter from entering into a gap between the ring member 19 and the
magnet member 34 of the multi-pole magnet 18, both forming
respective parts of the coil/magnetic element combination 17, to
thereby avoid damages to the electric generator 4. It is to be
noted that the sealing member 38 corresponds to a sealing member
referred to in Claim 7.
In this embodiment, the following functions and effects can be
obtained. since the electric generator 4 is disposed in the open
end portion between the outer member 1 and the inner member 2,
unlike the case in which the electric generator 2 is disposed
inside the bearing assembly such as in the first embodiment, the
electric generator 4 can be removed or mounted with no need to
dismantle the outer member and the inner member 2 of the bearing
assembly and, therefore, the electric generator 4 can easily be
maintained and serviced. Also, since the multi-pole magnet 18 of
the electric generator 4 is formed integrally with the sealing
member 31 at the open end portion between the outer member 1 and
the inner member 2, the electric generator 4 can be assembled
compact with minimized number of component parts, thereby
exhibiting an excellent assemblability.
Since the transmitting means 5 is constituted by the annular
transmitter 5A, the transverse section of the transmitter 5A can be
reduced and can, therefore, be disposed in a limited space
available in the vicinity of the bearing assembly. In other words,
where the box-shaped transmitting means 5 is employed as is the
case with the first embodiment, the transmitting means 5 is so
bulky that the surroundings of the wheel support bearing assembly
must be so designed as to provide a space for installation of the
box-shaped transmitting means 5. However, where the annular
transmitter 5A is employed, the space generally available around
the wheel support bearing assembly can be utilized for installation
of the transmitter 5A. As can readily be understood from FIG. 7,
the space generally available around the wheel support bearing
assembly, particularly that available in the vicinity of the open
end portion is often a very limited small space since it is
surrounded by the constant speed universal joint 15 and the fitting
member 12a of the wheel support bearing assembly. Even this very
small adjacent space can accommodate the transmitter 5A if the
latter is rendered to be annular in shape. In particular, since the
constant speed universal joint 15 is positioned close to such
adjacent space, such adjacent space is of a shape that can provide
a room in a radial direction rather than in an axial direction.
However, in the illustrated embodiment, the transmitter 5A is
arranged in overlapping relation with the outer periphery of the
coil/magnetic element combination 17 and, therefore, it can be
effectively and snugly accommodated within such adjacent space as
compared with the case in which the both are arranged axially.
Also, in the illustrated embodiment, since the annular transmitter
5A and the ring member 19 of the electric generator 4 are
integrated together, the combination of the transmitter 5A and the
electric generator 4 can be further compactized, enabling a space
for installation to be easily secured and the number of component
parts can also be reduced further.
Since the fitting ring 49 used to secure the coil/magnetic element
combination 17 and the transmitter 5A covers the multi-pole magnet
18 and, also, since the sealing member 38 is employed to seal
between the fitting ring 49 and the inner member 2, undesirable
ingress of foreign matter into the gap between the multi-pole
magnet 18 and the coil/magnetic element combination 17 can be
avoided. By this fitting ring 49 and the sealing member 38, damage
to the electric generator 4 which would result from ingress of the
foreign matter can be prevented.
The sealing member 11 provides a sealability at the bearing end
portion because of the sliding engagement between the seal lips 36a
to 36c, provided in the second sealing member 32, and the first
sealing member 31 and also because of the presence of the labyrinth
seal 37.
FIG. 9 illustrates a third embodiment of the present invention.
This embodiment is directed to a first generation of the wheel
support bearing assembly of the inner race rotating type wherein
the electric generator 4 serving as the rotation sensor is a thrust
type.
The outer member 1 serves as a member on a stationary side and is
in the form of an independent bearing outer race. The inner member
2 serves as a member on a rotational side and is made up of two
bearing inner races 2D arranged axially. None of the outer member 1
and the inner member 2 is provided with any wheel mounting flange
and a vehicle body fitting flange.
The sealing member 11 provided at the open end adjacent the
backside of the bearing assembly is of the same construction as the
sealing member used in the second embodiment (FIG. 7) and includes
the first and second sealing members 31 and 32. Even the electric
generator 4 is of the same structure as that in the second
embodiment and the multi-pole magnet 18 used therein is provided
integrally on the first sealing member 31. The coil/magnetic
element combination 17 of the electric generator 4 is, as is the
case with the second embodiment, fitted to the outer member 1 with
the ring member 19 coupled with the fitting ring 49. The fitting
ring 49 is of the same structure as that used in the second
embodiment and is provided with the sealing member 38.
The transmitting means 5 is, as is the case with that in the second
embodiment, in the form of the annular transmitter 5A, but is
positioned axially of the coil/magnetic element combination 17.
This annular transmitter 5A is fitted to an outer bottom face of
the groove-shaped portion 49a of the fitting ring 49.
Even in this embodiment, since the multi-pole magnet 19 of the
electric generator 4 is used as a component part of the sealing
member 11 and the wireless transmitting means 5 is employed in the
form of the annular transmitter 5A which is in turn integrated
together with the ring member 19 of the electric generator 4, there
is such advantages that the electric generator 4 can be easily
serviced and the space for installation of both the electric
generator 4 and the transmitting means 5 can be minimized. These
advantages can be equally obtained even in the embodiments which
will hereinafter be described.
FIG. 10 illustrates a fourth embodiment of the present invention.
The wheel support bearing assembly in this embodiment is a wheel
support bearing assembly of the inner race rotating type of a
second generation and the electric generator 4 serving as the
rotation sensor is the thrust type.
In this embodiment, the vehicle body fitting flange 1a is provided
in the outer member 1, and other structural features thereof are
similar to those shown in and described in connection with the
third embodiment with reference to FIG. 9.
FIG. 11 illustrates a fifth embodiment of the present invention.
The wheel support bearing assembly shown therein is a wheel support
bearing assembly of the inner race rotating type of a third
generation and is used for rotatably supporting the drive axle.
According to this embodiment, in the wheel support bearing assembly
of the third generation, the electric generator 4 of the thrust
type which concurrently serves as the rotation sensor is
incorporated in the sealing member 11, and the ring member 19 of
the electric generator 4 is arranged axially of the annular
transmitter 5A. The sealing member 11, the electric generator 4 and
the transmitting means 5A are, unless otherwise specified, similar
to those used in the second embodiment shown in and described with
reference to FIG. 7. Briefly speaking, the multi-pole magnet 18 is
fixed on the inner member 2 together with the first sealing member
31. The coil/magnetic element combination 17 is fixed on the outer
member 1 through the fitting ring 49 to which the ring member 19 is
fitted. The annular transmitter 5A is fixed on the fitting ring 49
and positioned on one side of the coil/magnetic element combination
17 remote from the fitting ring 49.
The outer member 1 is a member of one piece structure including the
vehicle body fitting flange 1a. The inner member 2 is made up of
the hub wheel 2A and a separate inner race forming member 2C
mounted on an outer periphery of one end of the hub wheel 2A. The
inner race forming member 2C is fixed on the hub wheel 2A by
axially fastening a fastening portion provided in the hub wheel 2A.
The inner member 2 has a wheel mounting flange 2a, and the inner
member 2 is fixed with a shaft portion of the constant speed
universal joint (not shown) inserted through an inner peripheral
hole thereof.
FIG. 12 illustrates a sixth embodiment of the present invention.
The wheel support bearing structure shown therein is substantially
similar to that according to the fifth embodiment shown in and
described with reference to FIG. 11, except that one open end of
the bearing assembly, that is, that portion of the bearing assembly
where the sealing member 11 is installed is provided with a reduced
diameter portion 81 defined in an outer periphery of the inner race
to provide an increase space for installation of the sealing member
11 with respect to a radially inward direction so that not only can
the multi-pole magnet 18 used therein have a correspondingly
increased surface area, but also the electric generator 4 can have
a correspondingly increased size. The reduced diameter portion 81
referred to above is set back radially inwardly of the inner race
forming member 2C by means of a step and is hence defined in the
inner race forming member 2C.
The formation of the reduced diameter portion 81 enables the use of
the electric generator 4 of a type having a reduced axial length.
In other words, the electric generator 4 even though increased in
size in a radial direction can have a correspondingly reduced axial
length. Thus, the structure in which the sealing member 11 is
permitted to have an increased size in the radially inward
direction by the provision of the reduced diameter portion 81 in
the outer periphery of the inner race as discussed above is
generally adopted in the wheel support bearing assembly in which
the component parts including the sealing member 11 and the
electric generator 4 are integrated together.
It is to be noted that in the sixth embodiment of the present
invention as discussed above, the annular transmitter 5A of the
transmitting means 5 is mounted externally on the coil/magnetic
element combination 17 while having been fixed to the fitting ring
49.
FIG. 13 illustrates a seventh embodiment of the present invention.
The wheel support bearing assembly shown therein is the inner race
rotating type of a third generation and is used to support a driven
axle. The electric generator 4 concurrently serving as the rotation
sensor is the thrust type.
Since this embodiment is for the support of the driven axle, the
inner member 2 is of a shape having no inner peripheral hole. Other
structural features thereof are substantially similar to those
described in connection with the fifth embodiment with reference to
FIG. 11.
FIG. 14 illustrates an eighth embodiment of the present invention.
The wheel support bearing assembly shown therein is an outer race
rotating type of a second generation, wherein the electric
generator 4 serving as the rotation sensor is the thrust type.
The outer member 1 has a wheel mounting flange 1b at one end
thereof which defines a front surface thereof. The inner member 2
is of a split type in which two bearing inner races 2D are arranged
axially. The sealing member, the electric generator 4 and the
transmitting means 5 are similar to those described in connection
with the third embodiment with reference to FIG. 9. In this
embodiment, the outer member 1 serves as a member on a rotating
side and, therefore, the transmitter 5A forming the transmitting
means 5 fitted to the outer member 1 rotates together with the
outer member 1. However, since the transmitter 5A used therein is
of an annular configuration, rotation of the transmitter 5A will
not adversely affect as a variation in detection signal on a
receiving side.
FIG. 15 illustrates a ninth embodiment of the present invention.
The wheel support bearing assembly shown therein is an inner race
rotating type of a first generation, wherein the electric generator
4 serving as the rotation sensor is the thrust type.
The outer member 1 serves as a member on the stationary side and is
constituted by an independent bearing outer race. The inner member
2 serves as a member on the rotating side and includes two bearing
inner races 2D arranged axially. The outer member 1 and the inner
member 2 have no wheel mounting flange and vehicle body fitting
flange.
The sealing member 11, the electric generator 4 and the
transmitting means 5A are, except for the following features,
similar to those described in connection with the third embodiment
with reference to FIG. 9. In the illustrated embodiment, the first
sealing member 31 of the sealing member 11 includes a cylindrical
portion 31a, an upright plate portion 31b bent radially outwardly
from the cylindrical portion 31a, a buck-turned upright plate
portion 31c turned radially inwardly from a free end of the upright
plate portion 31b, and an outer cylindrical portion 31d bent from a
radially inner end of the back-turned upright plate portion 31c so
as to extend outwardly from the bearing assembly. The back-turned
upright plate portion 31c extends a further radially inwardly than
the cylindrical portion 31a. The magnet member 34 of the multi-pole
magnet 18 is disposed on a side face of the back-turned upright
plate portion 31c facing outwardly of the bearing assembly. The
sealing member 31 is press-fitted into an outer peripheral surface
of one end portion of the inner member 2, while the back-turned
upright plate portion 31c has an inner peripheral portion
positioned outside the end face of the inner member 2.
Although the coil/magnetic element combination 17 of the electric
generator 4 is fitted to the outer member 1 by means of the fitting
ring 49 which is the same as that used in the third embodiment, the
sealing member 38 provided on an inner peripheral portion of this
fitting ring 49 defines an outer peripheral surface of the outer
cylindrical portion 31d of the first sealing member 31.
In the case of this embodiment, as compared with the third
embodiment, although a combination of the sealing member, the
electric generator 4 and the transmitter 5A may have an increased
axial length, the sealing member 38 is held in contact with the
outer peripheral surface of the outer cylindrical portion 31d and,
therefore, no sealing function will decrease even if the position
at which the first sealing member 31 is fitted axially changes to a
certain extent.
FIG. 16 illustrates a tenth embodiment of the present invention.
This embodiment is an outer race rotating type of a third
generation and is used to support the driven axle. The electric
generator 4 that serves as the rotation sensor is the thrust
type.
The outer member 1 has one end on a front side where the wheel
mounting flange 1b is formed. The inner member 2 is made up of two
inner race forming members 2E and 2F, the inner race forming member
2F being formed with the vehicle body fitting flange 2b. The
vehicle body fitting flange 2b is positioned on one side of the
rear end portion of the outer member 1 adjacent the rear surface.
The inner race forming member 2E is arranged at one end adjacent
the front surface and is fixed by means of a fastening portion
provided in the inner race forming member 2F.
The sealing member 11, the electric generator 4 and the
transmitting means 5 are, except for the following features,
similar to those described in connection with the third embodiment
with reference to FIG. 9. In this embodiment, the first sealing
member 31 of the sealing member 11 is press-fitted and mounted in a
portion between the raceway 9, defined on the outer peripheral
surface of the inner member 2, and the vehicle body fitting flange
2b. The coil/magnetic element combination 17 of the electric
generator 4 and the transmitter 5A are fitted to the outer member 1
by means of the same fitting ring 49 as that used in the third
embodiment, but the sealing member 38 provided in the inner
peripheral portion of this fitting ring 49 is held in sliding
engagement with the outer peripheral surface of the inner member
2.
In the case of this embodiment, although in the outer periphery of
the inner member 2, a groove-shaped space is created between the
end portion of the outer member I and the vehicle body fitting
flange 2b, such outer peripheral space of the inner member 2 is
effectively utilized to accommodate the electric generator 4 and
the transmitter 5A since the electric generator 4 and the annular
transmitter 5A overlap with each other in the axial direction.
FIG. 17 illustrates an eleventh embodiment of the present
invention. The wheel support bearing assembly in this embodiment is
the outer race rotating type of a second generation, in which the
thrust type electric generator 4 is employed as the rotation
sensor. This embodiment corresponds to the invention as set forth
in Claim 14.
The outer member 1 is a member on the rotating side and has a wheel
mounting flange 1b formed at one end thereof adjacent the front
surface. The inner member 2 is a member on the stationary side and
is of a split type including two bearing inner races 2D arranged
axially.
The transmitting means 5 is constituted by an annular transmitter
5A. This transmitter 5A is integrated together with the ring member
19 of the coil/magnetic element combination 17 by securing it to
the fitting ring 49A that is common to the coil/magnetic element
combination 17 forming a part of the electric generator 4. The
fitting ring 49A is a generally L-sectioned plate member including
a cylindrical portion 49Aa and an upright plate portion 49Ab, with
the coil/magnetic element combination 17 fitted around an outer
periphery of the cylindrical portion 49Aa, and the annular
transmitter 5A is fitted to an outer side face of the upright plate
portion 49Ab. The fitting ring 49A is mounted on an outer
peripheral surface of the inner member 2 by the cylindrical portion
49Aa having been press-fitted into the inner member 2, wherefore
the ring member 19 of the coil/magnetic element combination 17 and
the transmitter 5A are mounted on an outer periphery of one end of
the inner member 2.
The electric generator 4 is comprised of the multi-pole magnet 18
and the coil/magnetic element combination 17 that face with each
other, with the multi-pole magnet 18 fitted to an inner peripheral
surface of the outer member 1. The multi-pole magnet 18 is
comprised of a ring-shaped substrate 48 and a magnet member 34. The
ring-shaped substrate 48 is of a generally reversed L-section
including a cylindrical portion 48a and an upright plate portion
48b and is mounted with the cylindrical portion 48a press-fitted
into an inner peripheral surface of the outer member 1. The magnet
member 34 is fixed to the ring-shaped substrate 48 and, except for
this feature, this magnet member 34 is the same as the magnet
member 34 which has been shown in and described with reference to
FIG. 8.
The coil/magnetic element combination 17 is the same as the
coil/magnetic element combination 17 used in the embodiments shown
in FIG. 7, et seq., and includes the coil 20 accommodated within
the groove-shaped ring member 19. Although the coil/magnetic
element combination 17 has a generally flattened sectional shape in
which the width thereof in the axial direction is larger than the
width in the radial direction, but it may not be always flat in
sectional shape.
The sealing member 11 includes a sealing member 45 fitted to the
outer member 1 and held in sliding engagement with an outer
peripheral surface which is a groove side wall portion of the
groove-shaped ring member 19. The sealing member 45 is comprised of
a core metal 47 and an elastic member 46 formed integrally with the
core metal 47. The core metal 47 is formed to represent a generally
reverse L-sectional shape and is mounted as press-fitted into the
outer periphery of one end of the outer member 1. The elastic
member 46 includes lips 46b and 46c, held in sliding engagement
with an outer peripheral surface of the ring member 19 of the
coil/magnetic element combination 17, and a lip 46a held in sliding
engagement with the upright plate portion 49Ab of the fitting ring
49A.
In this structure, since sealing is achieved by causing the sealing
member 45 to contact the ring member 19 accommodating the coil 20
of the electric generator 4, the ring member 19 itself functions as
a sealing member and, therefore, the structure for sealing can
further be compactized. Also, not only the multi-pole magnet 18 of
the electric generator 4, but also a portion of the coil/magnetic
element combination is arranged in between the outer member 1 and
the inner member 2 and, therefore, protruding portions of the
electric generator 4 and the transmitter 5A that protrude outwardly
from the bearing assembly are reduced, thereby further reducing the
space for installation.
FIG. 18 illustrates a twelfth embodiment of the present invention.
The wheel support bearing assembly according to this embodiment is
the inner race rotating type of a third generation and is used for
the support of the drive axle. The electric generator 4 used
therein which serves as the rotation sensor is the thrust type.
The outer member 1 is of one piece structure including the vehicle
body fitting flange 1a. The inner member 2 includes a hub wheel 2A
and a separate inner race forming member 2B mounted on an outer
periphery of one end of the wheel hub 2A.
FIG. 19 illustrates a thirteenth embodiment of the present
invention. The wheel support bearing assembly used in this
embodiment is the inner race rotating type of a first generation,
wherein the electric generator 4 serving as the rotation sensor is
the radial type.
In this embodiment as well as the embodiments that follow, two
components, that is, an assembly A, comprised of the transmitter 5A
and the ring member 19, and an assembly B comprised of the
multi-pole magnet 18 and the sealing member 45B are utilized to
seal the open end between the outer member 1 and the inner member
2.
In the thirteenth embodiment shown in FIG. 19, the outer member 1
serves as a fixed side member and is made up of a single bearing
outer race. On the other hand, the inner member 2 serves as a
rotating side member and is made up of two bearing inner races 2D
arranged axially. The outer member 1 and the inner member 2 do not
have any wheel mounting flange and any vehicle body fitting
flange.
The transmitting means 5 is in the form of an annular transmitter
5A. This transmitter 5A is integrated together with the ring member
19 of the coil/magnetic element combination 17 by securing it to
the fitting ring 49B that is common to the coil/magnetic element
combination 17 forming a part of the electric generator 4. The
integrity so defined in this way serves as the assembly A on a side
adjacent the coil. The sealing member 11 for sealing the open end
includes a sealing member 45B to which the multi-pole magnet 18 of
the electric generator 4 is fitted. The sealing member 45B includes
a sealing core metal 47B and an elastic member 46B with the elastic
member 46B held in sliding contact with the fitting ring 49B. The
sealing member 45B and the multi-pole magnet 18 altogether
constitute the assembly B. The ring member 19 of the coil/magnetic
element combination 17 is fitted to an outer peripheral surface of
one end portion of the inner member 2 through the fitting ring 49B,
and the end of the outer member 1 is located at a potion retracted
axially inwardly of the inner member 2 towards an intermediate
portion of the bearing assembly a distance about equal to the width
of the coil/magnetic element combination 17.
The mounting ring 49B includes a first cylindrical portion 49Ba
having one end portion formed with a first upright plate portion
49Bb extending radially outwardly, a second cylindrical portion
49Bc, and a second upright plate portion 49Bd extending radially
outwardly therefrom. The coil/magnetic element combination 17 is
fitted to the mounting ring 49B with the ring member 19 mounted on
the outer peripheral surface of the first cylindrical portion 49Ba
of the mounting ring 49B and held in contact with the first upright
plate portion 49Bb. The annular transmitter 5A is fitted to an
outer side face of the second upright plate portion 49Bb of the
fitting ring 49B. The mounting ring 49B is press-fitted into the
outer peripheral surface of the end of the inner member 2 with the
first cylindrical portion 49Ba.
The sealing core metal 47B is of a shape including a first
cylindrical portion 47Ba having one end formed with a first upright
plate portion 47Bb extending radially inwardly, a second
cylindrical portion 47Bc and a second upright plate portion 47Bd
extending radially inwardly therefrom. This sealing core metal 47B
is fitted in position with the first cylindrical portion 47Ba
press-fitted into the outer peripheral surface of the end of the
outer member 1. The elastic member 46B includes a plurality of lips
46Ba to 46Bc slidingly engaged with the second cylindrical portion
49Bc and the second upright plate portion 48Bd of the fitting ring
49B.
Although as is the case with that in the first embodiment shown in
FIGS. 1 to 5 the electric generator 4 is the radial type, contrary
to the first embodiment the multi-pole magnet 18 is positioned on
the side of the outer periphery whereas the coil/magnetic element
combination 17 is positioned on the side of the inner
periphery.
The multi-pole magnet 18 includes a cylindrical substrate 48C and
the magnet member 34 and is press fitted into an inner peripheral
surface of the second cylindrical portion 47Bc of the sealing core
metal 47B. The magnet metal 34 is substantially the same as the
magnet member 34 shown in and described with reference to FIG. 3,
except that it is fixedly secured to the cylindrical substrate 48C
as described above.
The coil/magnetic element combination 17 is made up of the ring
member 19 made of a magnetic material and accommodating the coil
20. The ring member 19 is substantially the same as the ring member
19 of the coil/magnetic element combination 17 which has been
described in connection with the first embodiment (FIG. 1) with
reference to FIGS. 4 and 5, except that the orientation of magnetic
polarity is different. In other words, the ring member 19 shown in
the example of FIG. 19 has a sectional shape which is groove-shaped
as is the case with the ring member 19 used in the example of FIGS.
4 and 5 and includes a plurality of interleaved claws 21a and 22a
bent from open edges of the side faces of the groove in respective
directions opposed to each other and alternating in a direction
circumferentially thereof. It is, however, to be noted that the
coil/magnetic element combination 17 used in the embodiment of FIG.
19 is, unlike that in the example shown in FIGS. 4 and 5, has its
groove opening oriented in a direction radially outwardly with
respective magnetic poles defined by the interleaved claws 21a and
22a oriented radially outwardly. Even in the ring member 19 used in
the example shown in FIG. 19, the interleaved claws 21a and 22a may
be tapered as is the case with the example shown in FIG. 6.
In the structure described above, since the sealing member 11 and
the electric generator 4 and the transmitting means 5 are
constituted by the two assemblies, the number of component parts is
small and assemblability is excellent.
FIG. 20 illustrates a fourteenth embodiment of the present
invention which is directed to the wheel support bearing assembly
of the inner race rotating type of a second generation. In this
wheel support bearing assembly, the electric generator 4 which
serves as the rotation sensor is the radial type.
The outer member 1 is of one piece structure including the wheel
fitting flange 1a on the outer periphery thereof. The inner member
2 includes two bearing inner races 2D arranged axially.
The sealing member 11, the electric generator 4 and the
transmitting means 5 are substantially the same as those used in
the thirteenth embodiment described with reference to FIG. 19 and
are constituted by the two assemblies A and B.
FIG. 21 illustrates a fifteenth embodiment of the present invention
which is directed to the wheel support bearing assembly for the
support of a driven axle. This wheel support bearing assembly is
the inner race rotating type of a third generation and the electric
generator 4 serving as the rotation sensor is the radial type.
The outer member 1 is of one piece structure including the vehicle
body fitting flange 1a. The inner member 2 is constituted by the
hub wheel 2A and the separate inner race forming member 2C mounted
on the outer periphery of the end of the hub wheel 2A. The inner
race forming member 2C is fixed in position by fastening a
fastening portion, provided in the hub wheel 2A, to connect it to
the hub wheel 2A axially. The inner member 2 is a non-perforated
member having no inner bore and has the wheel mounting flange 2a at
one end thereof.
The sealing member 11, the electric generator 4 and the
transmitting means 5 are substantially the same as those used in
the thirteenth embodiment shown in FIG. 19 and are constituted by
the two assemblies A and B.
FIG. 22 illustrates a sixteenth embodiment of the present
invention. The wheel support bearing assembly according to this
embodiment is for the support of a drive axle and is the inner race
rotating type of a third generation. The electric generator 4 that
serves as the rotation sensor is the radial type.
In this embodiment, the inner member 2 has an inner diametric hole
2h. Other structural features thereof are substantially similar to
those in the fifteenth embodiment shown in FIG. 21.
FIG. 23 illustrates a seventeenth embodiment of the present
invention. The wheel support bearing assembly according to this
seventeenth embodiment is the outer race rotating type of a second
generation and the electric generator 4 that serves as the rotation
sensor is the radial type.
The outer member 1 is of one piece structure including the wheel
fitting flange 1a on the outer periphery thereof. The inner member
2 includes the two bearing inner races 2D arranged axially
thereof.
The sealing member 11, the electric generator 4 and the
transmitting means 5 are substantially similar to those in the
thirteenth embodiment shown in FIG. 19 and are constituted by the
two assemblies A and B.
FIG. 24 illustrates an eighteenth embodiment of the present
invention. The wheel support bearing assembly shown therein is
substantially similar to that according to the sixteenth embodiment
shown in and described with reference to FIG. 22, except that the
following structural features are added to the wheel support
bearing assembly of FIG. 24. More specifically, the multi-pole
magnet 18 and the coil/magnetic element combination 17 of the
electric generator 4 are positioned radially inwardly and radially
outwardly relative to each other, respectively. The transmitter 5A
used therein is of an annular configuration and is positioned
radially outwardly of the electric generator 4.
In this structure, since the annular transmitter 5A is used and
positioned radially outwardly of the electric generator 4, the
transmitter does not protrude axially of the wheel support bearing
assembly such as observed in the sixteenth embodiment shown in FIG.
22 and, therefore, utilization of the space axially adjacent the
wheel support bearing assembly can advantageously be maximized
particularly where the constant speed universal joint is positioned
closely to the wheel support bearing assembly. Also, any wiring
between the transmitter 5A and the electric generator 4 can also be
dispensed with.
FIGS. 25 to 27 illustrates a nineteenth embodiment of the present
invention. According to this embodiment, the electric generator 4
has the following structural features. More specifically, in this
embodiment, a pair of multi-pole magnets 18 and 18 are employed in
combination with a ring member 69. As best shown in FIG. 25B, the
ring member 69 includes a casing portion 69a and a magnetic pole
portion 69b positioned radially inwardly of the casing portion 69a.
While the coil 20 of the electric generator 4 is accommodated
within the casing portion 69a of the ring member 69, those
multi-pole magnets 18 and 18 are positioned on respective sides of
the magnetic pole portion 69b extending axially inwardly of the
annular space between the inner and outer members 2 and 1, with the
multi-pole magnets 18 and 18 consequently disposed one inside the
other with respect to the radial direction. The ring member 69 of
the structure described above is fitted to the outer member 1
whereas the multi-pole magnets 18 and 18 are secured to a common
annular carrier 71 so as to assume respective positions on the
sides of the magnetic pole portion 69b, said annular carrier 71
being in turn mounted on the inner member 2. It is to be noted that
the annular carrier 71 which has been described as carrying the
multi-pole magnets 18 and 18 and as mounted directly on the inner
member 2 may alternatively employed for each of the multi-pole
magnets 18 and 18 and may be mounted on the inner member 2 through
the mounting ring 49B.
The casing portion 69a of the ring member 69, in which the coil 20
is accommodated therein represents a generally C-shaped section,
and as best shown in FIGS. 26 and 27, has neighboring side edges
each having a plurality of prongs 21a or 21b formed integrally
therewith. FIGS. 26 and 27 are views of the ring member 69 as
viewed from different angles, respectively. The prongs 21a integral
with the lower side edge of the casing portion 69a extend from an
inner periphery of the casing portion 69a. Those prongs 21a and 21b
are, as is the case with the ring member 19 shown in, for example,
FIG. 5, FIG. 6, interleaved with each other so as to define
alternating magnetic poles. The interleaved arrangement of those
prongs 21a and 21b in a direction circumferential of the ring
member 69 constitutes the magnetic pole portion 69b referred to
above. The whole of the ring member 69 is made of magnetic
material.
The wheel support bearing assembly according to this embodiment
shown in FIG. 25 to 27 are, except for the electric generator 4,
similar to the wheel support bearing assembly according to the
sixteenth embodiment shown in and described with reference to FIG.
22, in which the transmitter 5A is positioned radially outwardly of
the electric generator 4 and is mounted on a mounting ring 45B.
In the case of this embodiment, since the multi-pole magnets 18 and
18 are positioned on the respective sides of the magnetic pole
portion 69b of the ring member 69 carrying the coil 20, the surface
area confronting the multi-pole magnets 18 and 18 can be increased
without altering the surface area of the magnetic pole portion 69b
including the prongs 21a and 21b. Accordingly, the magnetic fluxes
interlinking with the coil 20 can be increased to thereby increase
the power output of the electric generator 4. By way of example, as
compared with the use of the single multi-pole magnet 18, the
quantity of the magnetic fluxes that is twice that obtained with
the single multi-pole magnet 18 can be secured and, hence, the
power output correspondingly increase twofold.
Since the space for installation of the electric generator 4
employed in this type of the wheel support bearing assembly is
severely limited, it is considered feasible to use the electric
generator of a compact size, but capable of providing an increased
power output. In particular, in the case of a small diameter
bearing, for a given transverse sectional surface area of the coil
20 of the electric generator 4 (i.e., without the number of turns
of the coil 5 being changed), a problem has been recognized in that
the total surface of the multi-pole magnet 18 can be reduced and
the electric power output is correspondingly reduced.
In order to increase the electric power output of the generator,
one or a combination of four factors, i.e., increase of the
magnetic force, reduction of the gap, increase of the number of
turns of the coil (increase of the capacity) and increase of the
magnet-to-magnet surface area, can be contemplated. Of them,
increase of the magnetic force is limited in view of material,
reduction of the gap is difficult to achieve because of a
precision, and increase of the number of turns of the coil is
incompatible with compactization.
However, according to the nineteenth embodiment discussed above,
since the two multi-pole magnets 18 and 18 are positioned on the
respective sides of the same magnetic pole portion 96b, it is
possible to increase interlinking magnetic fluxes without altering
the capacity of and the magnetic force produced by the coil 20 of
the electric generator 4, and hence to increase the power output of
the electric generator 4. Although the two multi-pole magnets 18
and 18 are employed, as compared with increase of the coil
capacity, it is possible to easily achieve compactization. Where
the ring member 69 that serves as a yoke is so configured and so
shaped as to define the generally C-sectioned casing portion 69a
and the magnetic pole portion 69b extending therefrom such as shown
in FIGS. 26 and 27, the assembly including the ring member 69 and
the two multi-pole magnets 18A and 18B can be snugly and neatly
accommodated and the total capacity of the electric generator 4 and
the multi-pole magnets 18 and 18 can advantageously be reduced,
making it possible for the system as a whole to be assembled
compact.
Also, the structure in which the multi-pole magnets 18 and 18 are
positioned on the respective sides of the magnetic pole portion 69b
such as in the nineteenth embodiment is particularly advantageous
in that even though the magnetic pole portion 69b is radially
displaced during assemblage or rotation, the sum of the magnetic
gaps between one multi-pole magnet 18 and the magnetic pole portion
69b and between the other multi-pole magnet 18 and the magnetic
pole portion 69b does not vary and, accordingly, the influence
which such variation would be brought upon the power generating
performance is minimal as compared with that occurring where only
one multi-pole magnet 18 is employed.
In the foregoing embodiment described with reference to FIGS. 25 to
27, the ring member 69 carrying the coil 20 and the multi-pole
magnets 18 and 18 have been shown and described as mounted on the
outer and inner members 1 and 2, respectively. However, they may be
reversed in position relative to each other, that is, the ring
member 69 and the multi-pole magnets 18 and 18 may be mounted on
the inner and outer members 2 and 1, respectively. In such
alternative case, either of the outer and inner members 1 and 2 may
be a rotating side. In addition, the nineteenth embodiment has been
described as applied to the wheel support bearing assembly of the
third generation used to support the drive axle, but the
arrangement in which the multi-pole magnets 18 and 18 are
positioned on the respective sides of the magnetic pole portion 69b
can be applied to any type of the wheel support bearing assembly
regardless of the generation and also regardless of whether it is
used in association with the drive axle or whether it is used in
association with the driven axle.
Hereinafter, application of any one of the wheel support bearing
assemblies of the foregoing embodiments to an anti-skid brake
system will be described with particular reference to FIGS. 28 to
34. It is, however, to be noted that although the anti-skid brake
device can work satisfactorily with the wheel support bearing
assembly of any of the previously described embodiments, the
following description proceeds with the wheel support bearing
assembly of the first embodiment (FIG. 1) as applied to the
anti-skid brake device. The anti-skid brake device as shown in FIG.
28 is an apparatus wherein the braking force of a brake 82 is
controlled by detecting the number of revolution of wheels 13 with
the use of the wheel support bearing assembly of FIG. 1 and in
response to a detection signal thereof. Each wheel 13 is rotatably
supported by the automotive body structure 12 through the wheel
support bearing assembly 33. The wheel support bearing assembly 33
employed is in the form of the wheel support bearing assembly
described with reference to and shown in FIGS. 1 to 6 in connection
with the first embodiment of the present invention, and is of the
design in which the rolling elements 3 are interposed between a
wheel support member 1, which serves as the outer member, and a
rotary member 2 which serves as the inner member. The wheel support
member 1 includes a bearing member of stationary side, and the
rotary member 2 includes a bearing member of rotary side. The wheel
support member 1 is supported by a suspension system (not shown),
protruding downwardly from the automobile body structure 12,
through a knuckle 85. The rotary member 2 includes the wheel
mounting flange 2a formed on an outer periphery of one end thereof,
to which the wheel 13 is fitted. The wheel 13 is, so far shown
therein, a front (steering) wheel, and the rotary member 2 of the
wheel support bearing assembly 33 has the opposite end connected to
an axle (not shown) through the constant speed universal joint 15.
This rotary member 2 includes an integral part which defines the
outer race of the constant speed universal joint 15.
A pulsar ring 18 which is mounted on the rotary member 2, and a
sensor 17 is mounted on the wheel support member 1 in opposition to
the pulsar ring 18. The pulsar ring 18 and the sensor 17 altogether
constitute the electric generator 4 and define the rotor and the
stator of the electric generator 4, respectively. Each part of this
embodiment is the same structure as shown in FIGS. 1 to 5. The
detection signal from the sensor 17 is supplied through a wireless
transmitting means 27 to a controller 86. The controller 86 is a
means for controlling the braking force of the brake 82. The
wireless transmitting means 27 includes a transmitting means (a
transmitting unit) 5 electrically connected with the sensor 17
through a connector 41 and mounted on a portion of the outer
periphery of the wheel support member 1, and a receiving means (a
receiving unit) 25 mounted on the automobile body structure 12. The
receiving means 25 is installed within, for example; a tire housing
12a defined in the automobile body structure 12.
The brake 82 is used to brake the wheel 13 by engagement with a
frictional member (not shown) such as, for example, a brake drum or
a brake disc provided on the wheel 13 and includes a hydraulic
cylinder or the like. Operation of a brake operating member 87 such
as, for example, a brake pedal is converted into a hydraulic
pressure by means of a converting means 88 and is then transmitted
to the brake 82 after having increased in pressure.
A braking force regulating means 89 is a means for regulating the
braking force of the brake 82 and regulates the braking force
according to a command from the controller 86. The braking force
regulating means 89 is provided on a hydraulic circuit at a
location between the brake 82 and the converting means 88.
The controller 86 is, more specifically, a means for applying a
braking force regulating command to the braking force regulating
means 89 according to the number of wheel revolutions detected by
the rotation sensor 17. As a parameter indicative of the number of
revolutions of the wheel detected by the sensor 17, a sensor signal
outputted from the receiving unit 25 of the wireless transmitting
means 27 is utilized. As will be described later, the receiving
unit 25 is used to detect not only the sensor signal, but also a
radio field strength signal indicative of the strength of radio
waves, and the controller 86 is operable to determine control of
the braking force in dependence on the sensor signal and the radio
field strength signal. This controller 86 includes a computer such
as, for example, a microcomputer, and a computer executable program
(not shown) executed by the computer. This computer executable
program describes an algorithm for determining the control of the
braking force in dependence on the sensor signal and the radio
field strength signal. The controller 86 may be constituted by an
electronic circuit in which control procedures are set up.
FIG. 29 illustrates a block circuit diagram of the wireless
transmitting means 27. The wireless transmitting means 27 is
operable with feeble radio waves and employs a frequency modulation
(FM) system. The transmitter 5 is so designed to modulate a carrier
wave based on the sensor output signal from the sensor 17 and to
transmit a feeble radio wave and includes an oscillating and
modulating circuit 92 and a transmitting antenna 93. The
oscillating and modulating circuit 92 includes an oscillator for
oscillating a carrier wave of a predetermined frequency and a
modulator for modulating the carrier wave from the oscillator with
the sensor output signal from the sensor 17. This oscillating and
modulating circuit 92 is electrically powered by an electric power
source 94 utilizing the electric power generated by the electric
generator 4 also serving as a dynamo type rotation sensor.
A receiving unit 25 includes a receiver antenna 95, a tuning
circuit 96 for tuning to the received signal, a demodulating
circuit 97 for demodulating the received and tuned signal, and an
output circuit 98 for performing a predetermined process on the
output from the demodulating circuit 97 and also for outputting a
signal (ABS signal) to be supplied to the controller 86 shown in
FIG. 28. More specifically, the tuning circuit 96 is operable to
tune the received signal and then to convert the received signal
into an intermediate frequency signal, and the demodulating circuit
97 is employed in the form of an frequency demodulating circuit
operable to demodulate the intermediate frequency signal. The
tuning circuit 96 includes a local oscillator 99 for generating a
local oscillation signal of a predetermined frequency, and an FM
mixing circuit 100 for mixing the received signal and the local
oscillation signal to provide the intermediate frequency signal.
The demodulating circuit 97 is operable to output a radio field
strength signal indicative of the strength of the radio field of
the received signal along with an operation to output the
demodulated signal corresponding to the sensor output signal from
the sensor 17. Both of those signals are inputted to the output
circuit 98. The demodulated signal is in the form of a frequency
modulated pulse signal.
The output circuit 98 is operable, as the predetermined process, to
output a duplex signal in which the sensor output signal, that is,
the demodulated signal outputted from the demodulating circuit 97,
and the radio field strength signal are duplexed together. This
duplex signal is hereinafter referred to as an ABS signal. The
duplexing is a process of synthesizing a signal added with a direct
current offset by the radio field strength signal to the sensor
output signal, that is, the demodulated signal. The duplex signal,
that is, the ABS signal is of a kind from which contents of the
signal can be detected in terms of the voltage.
The ABS signal outputted from the output circuit 98 can be
available in one of the following three forms: (1) When the
demodulated signal (pulse signal) appears and the radio field
strength signal indicates the strong radio field strength.
This signal form is generated during a normal operation. (2) When
the radio field strength signal indicates the feeble radio field
strength (or the zero radio field strength) regardless of the
presence or absence of the demodulated signal (pulse signal).
This signal form is generated when the transmitter is abnormal or
halted, or when an unstable operation takes place as a result of
lack of a sufficient operating electric power. (3) When the
demodulated signal (pulse signal) does not appear and the radio
field strength signal indicates the strong radio field
strength.
This signal form is generated when jamming radio waves are
present.
Referring to FIG. 28, the controller 86 determines a control of the
braking force in dependence on the sensor output signal and the
radio field strength signal both outputted from the receiving unit
25 and apply a control command appropriate to a result of
determination to the braking force regulating means 89. By way of
example, the controller 86 is operable to control not to perform an
anti-skid braking operation in dependence on the sensor output
signal and the radio field strength signal in the event that no
predetermined condition is satisfied. The predetermined condition
referred to above is such that a normal operation is determined in
reference to the sensor output signal and the radio field strength
signal. The condition required to determine the occurrence of the
normal operation is determined is satisfied when the demodulated
signal appears and the radio field strength signal indicates the
strong radio field strength.
In the event that the sensor output signal and the radio field
strength signal both outputted from the receiving unit 25 are
represented by the duplex signal referred to above, the controller
86 responds to the duplex signal to determine a control of the
braking force appropriate to the sensor output signal and the radio
field strength signal.
Where the receiving unit 25 is constructed as discussed with
reference to FIG. 29, the ABS signal of one of the forms (1) to (3)
discussed above is outputted from the receiving unit 25 as the
duplex signal in which the sensor output signal and the radio field
strength signal are duplexed. In such case, the predetermined
condition required to determine whether or not the anti-skid
braking operation is carried out is when the demodulated signal
appears and the radio field strength signal indicates the strong
radio field strength, as mentioned under item (1) above. Where
regardless of the presence or absence of the demodulated signal,
the radio field strength signal indicates the feeble radio field
strength as mentioned under item (2) above, and where the
demodulated signal (pulse signal) does not appear and the radio
field strength signal indicates the strong radio field strength as
mentioned under item (3) above, no anti-skid braking operation is
performed. Determination of the condition in which the demodulated
signal appears and the radio field strength signal indicates the
strong radio field strength as mentioned under item (1) above can
take place, for example, when as can be understood from the
waveforms shown in, and as will be described with reference to,
FIGS. 30, 32 and 34, the duplex signal (the ABS signal) indicates a
voltage in a higher region than a predetermined voltage.
FIG. 31 illustrates an exemplary circuit construction of the output
circuit 98 discussed above. This output circuit 98 includes a
series circuit of two series-connected voltage dividing resistors
R1 and R2, which is interposed between a power source terminal VCC
and a ground terminal GND, and a switching transistor 104 with the
base of the switching transistor 104 adapted to receive the
demodulated signal. Another switching transistor 106 is connected
between a junction 105 of the series-connected resistors R1 and R2
and the ground terminal GND and has its base adapted to be applied
with the radio field strength signal through an inverter 107. The
ABS signal, which is the duplex signal, is outputted from the
junction 105.
Where the output circuit 98 is constructed as shown in FIG. 31, the
output from this output circuit 98 represents such a waveform as
shown in FIG. 32 depending on one of the previously discussed
conditions for the demodulated signal and the radio field strength
signal.
Specifically, in the event of the condition (1) (when the
demodulated signal appears and the radio field strength signal
indicates the strong radio field strength), the radio field
strength signal assumes a HIGH level, which is in turn inverted by
an inverter 107 and is then applied to the base of the transistor
106, and therefore, the transistor 106 is switched off. Also, the
demodulated signal corresponding to the detection signal from the
sensor 17 represents a pulse signal in which HIGH and LOW levels
are alternately repeated. Since this demodulated signal is applied
to the base of the transistor 104, the transistor 104 is
alternately switched on and off. Accordingly, the waveform of the
output from the output circuit 98 outputted during this condition
(1) is such as indicated by a region (1) in FIG. 32.
In the event of the condition (2) (when the radio field strength
signal indicates the feeble radio field strength regardless of the
presence or absence of the demodulated signal), the radio field
strength signal assumes a LOW level and is, after having been
inverted by the inverter 107, applied to the base of the transistor
106. Accordingly, the transistor 106 is switched on and, hence, the
output from the output circuit 98 during this condition (2)
represents 0V as indicated by (2) in FIG. 32.
In the event of the condition (3) (when the demodulated signal does
not appear and the radio field strength signal indicates the strong
radio field strength), the radio field strength signal assumes a
HIGH level and the transistor 106 is correspondingly switched off.
However, since no demodulated signal is applied to the transistor
104 associated with the demodulated signal, the transistor 106 is
held in a conducting state and, accordingly, the output from the
output circuit 98 during this condition (3) represents a constant
voltage level as shown by (3) in FIG. 32.
The output circuit 98 discussed above may have an alternative
circuit construction such as shown in FIG. 33. In this alternative
example, supply of the electric power and that of the output signal
are carried out by means of a single line. Specifically, the output
circuit 98 includes a series connected circuit of voltage dividing
resistors R3 and R4, which is connected between the power terminal
VCC in the controller 86 and the ground terminal GDN in the
receiving unit 25, and a switching transistor 114 with the base of
the transistor 114 adapted to be applied with the demodulated
signal. Another transistor 116 and a resistor R5 are connected
between a junction 115 of the resistors R3 and R4 and the ground
terminal GDN, with the base of the transistor 116 adapted to be
applied with the radio field strength signal through the inverter
117. It is to be noted that one R3 of the resistors R3 and R4 is
provided in the controller 86 so that on a side of the controller
86, the ABS signal can be outputted from the junction 115. On the
side of the output circuit 98, the junction 115 is also connected
with a stabilizing power circuit through a resistor R6.
With the output circuit 98 of the structure shown in FIG. 33, the
output from this output circuit 98 represents such a waveform as
shown in FIG. 34 depending on one of the previously discussed
conditions for the demodulated signal and the radio field strength
signal.
Specifically, in the event of the condition (1) (when the
demodulated signal appears and the radio field strength signal
indicates the strong radio field strength), the transistor 116
associated with the radio field strength signal is switched off and
the transistor 104 associated with the demodulated signal is
alternately switched on and off. Accordingly, the waveform of the
output from the output circuit 98 during this condition (1) is a
waveform of the normal operation such as indicated by a region (1)
in FIG. 34.
In the event of the condition (2) (when the radio field strength
signal indicates the feeble radio field strength regardless of the
presence or absence of the demodulated signal), the transistor 116
associated with the radio field strength signal is switched on and,
hence, the output from the output circuit 98 during this condition
(2) represents such a waveform as indicated by (2) in FIG. 34.
In the event of the condition (3) (when the demodulated signal does
not appear and the radio field strength signal indicates the strong
radio field strength), the transistor 116 associated with the radio
field strength signal is switched off and the transistor 114
associated with the demodulated signal is switched on. Accordingly,
the output from the output circuit 98 during this condition (3)
represents a voltage level as shown by (3) in FIG. 34.
FIG. 30 illustrates a waveform chart showing a relation among the
rotational speed of the wheel 13 detected by the sensor 17, the
output transmitted from the transmitting unit 5, the radio field
strength signal, the demodulated signal, and the ABS signal.
The operation of the circuit arrangement discussed above will now
be described. Referring again to FIG. 28, the signal indicative of
the number of revolutions of the wheel detected by the sensor 17 is
transmitted wireless from the transmitting unit 5 in the wheel
support bearing assembly 1 to the receiving unit 25 on the side of
the automobile body structure, and the controller 86 performs the
control of the braking force in dependence on the ABS signal
outputted from the receiving unit 25.
Since at this time the ABS signal represents one of the output
waveforms as shown in FIG. 32 or FIG. 34 depending on one of the
previously discussed conditions with respect to the demodulated
signal and the radio field strength signal, the controller 86 can
determine in reference to the ABS signal supplied thereto, if the
transmitting unit 5 is operating normally, halted or disturbed by
the jamming radio waves and, accordingly, the control appropriate
to the condition can be performed. In other words, in the event
that the controller 86 determines that the transmitting unit 5 is
disturbed by the jamming radio waves or halted, it is possible to
refrain the control of the braking force from being erroneously
performed based on the result of determination.
According to the embodiment shown in and described with reference
to FIGS. 28 to 34, the output circuit 98 of the receiving unit 25
is so configured as to output the ABS signal that represents the
voltage of the duplex signal in which the demodulated signal and
the radio field strength signal are duplexed. Accordingly, the
number of wiring lines which would be required between the
receiving unit 25 and the controller 86 can advantageously be
reduced. In particular, where the output circuit 98 is of the
structure shown in FIG. 33, the single line is sufficient to supply
the electric power and to output the signal and, therefore, the
number of the wiring lines can further be reduced advantageously.
Accordingly, this contributes to reduction in weight of the
automotive vehicle as a whole.
Also, in this embodiment, since the frequency modulation system is
employed, utilization of the signal outputted from the sensor 17
and subsequently outputted from the transmitter 5 can facilitate
the receiving unit 25 to sufficiently and easily detect the signal
component indicative of the rotation speed and the signal component
indicative of the radio field strength.
Although the present invention has been fully described in
connection with the preferred embodiments thereof with reference to
the accompanying drawings which are used only for the purpose of
illustration, those skilled in the art will readily conceive
numerous changes and modifications within the framework of
obviousness upon the reading of the specification herein presented
of the present invention. Accordingly, such changes and
modifications are, unless they depart from the scope of the present
invention as delivered from the claims annexed hereto, to be
construed as included therein.
* * * * *